You are correct that I have written about this many times over the years. One of the objections I had to the writing of someone who, until about three years ago, used to write about c 603 was that she seemed to believe if a lay person made private vows of the evangelical counsels they ceased being a lay person. Were that so, there could be no lay hermits (and perhaps no lay persons at all -- depending on how many kept the evangelical counsels as the church asks us ALL to do)!! But this can be shown to be untrue for at least two basic reasons, (1) I myself, though consecrated and perpetually professed as a diocesan hermit am still a lay person in the hierarchical sense of that term; that makes me a lay hermit since I am not a cleric (in the alternate, or vocational sense of the term lay, I am a (publicly) consecrated person, and so am a consecrated not a lay hermit). The ambiguous and confusing dual meaning of lay is one reason non-canonical hermit vs canonical hermit is a simpler and more accurate way of distinguishing the two) and (2) as noted above, every baptized person in the church is called upon to live out the evangelical counsels according to her or his own state of life! The profession of the counsels does not, of itself, initiate us into the consecrated state; that requires an act of God which occurs during the Rite of Religious Profession culminating in the solemn prayer of consecration. (We may call the entire Rite either profession or consecration as an act of synecdoche, but the making of vows and the consecration of the one making vows are two distinct but profoundly related acts occurring during the single Rite.) In the hierarchical sense of the word lay, all non-clerics, including all men and women religious, are laity.
In creating c 603 the Church was attempting to rectify a long-overdue oversight, namely, the making of the eremitical vocation a state of perfection (that is, an instance of the consecrated state of life). Bishop Remi de Roo noted that hermits had long been overlooked and he listed the good they provided for the faith of the church. Much of Vatican Council II was a matter of going back to the sources, and in this particular intervention, De Roo was serving as bishop protector of a dozen or so hermits who had had to leave their monasteries and solemn professions to be secularized in order to pursue the eremitical solitude they felt called to. Since monastic life had its roots in the Desert Abbas and Ammas, and since the apex of monastic life was also often understood as solitary union with God and the eremitical state, it made sense that secular (that is, non-religious) hermits, who, despite some eccentrics and outright nutcases were also marked by holiness and a prophetic presence in the church, should have the dignity of their lifestyles recognized by initiating them canonically into the consecrated state of life. Thus, the Church listened to Bishop De Roo and eventually, with the revision of the Code of Canon Law, published a canon for solitary hermits and allowing their initiation into the consecrated state.
Of course, not everyone who is or calls themselves a hermit seeks or is suited to consecration as a canonical hermit. The Church does not automatically admit every person to profession and consecration. I will say, however, that some of us, in accord with The Hermit's Way of Life in the Local Church** guidelines, are working to develop better processes of discernment and formation for such hermit candidates, processes which will be more individualized or tailored to the needs of each candidate and the way the Holy Spirit works in his/her case. Over time it is hoped that all dioceses will be able to use a process more like the mentoring done by Elder Abbas and Ammas in the desert and less laden with arbitrary canonical time frames and other considerations that are more suitable to cenobitical life. Canon 603 itself contains all that is needed to discern and form such vocations in a way allowing diocesan personnel to work with an experienced hermit and to journey with a "candidate" until s/he is ready for profession and later, perpetual profession and consecration, discerns a different call, or demonstrates unsuitability for those steps instead.Again, no one is denigrating non-canonical hermits through the ages!! In fact, canon 603 came to be precisely because the church recognized that eremitical life was an outstanding way to holiness and throughout its history, had produced many outstanding examples of this. With canon 603, the Church honors them and, again, is simply trying to rectify a longstanding failure to regard the importance of the hermit vocation by making it possible for hermits in the lay state of life to be initiated into the consecrated state if a genuine call is mutually discerned. For those who find canon law onerous, who have no desire to undergo a several-year process of discernment and formation with others (diocesan personnel and canonical hermit mentors), who believe that the Church's mediation of one's call and response to this vocation in c 603 and its necessary structures get in the way of a "direct" relationship with God, or who perhaps are simply way more individualistic than all that allows for, the fact is that one can always become a hermit in the way people have done since the third century and earlier, namely, do it on one's own as a hermit in the lay (non-canonical) rather than the consecrated state.
The Church has provided sufficient choices here for everyone. Is God calling you to the consecrated state? Then join an institute of consecrated life or petition for admission to profession and consecration through the diocesan offices of Vicar for Religious and Bishop. If you desire to go it the longstanding way of 20 centuries of church history, the way of the Desert Abbas and Ammas, then accept that you will do it in the lay state by virtue of the freedom granted you by baptism (or baptism and the clerical state if you are in Orders). I don't think any other categories of hermit life are necessary. Meanwhile, every hermit is called to live the following terms of canon 603 in some way, shape, or form: evangelical counsels (like all Christians), assiduous prayer and penance, the silence of solitude, stricter separation from the world, all lived for the salvation of the world. None of these of themselves make a lay person other than a lay person.One final reminder, the Church recognizes that the eremitical vocation in the consecrated state belongs first of all to the church herself and only thereafter to individual hermits. She extends the gift of initiation into the consecrated state and this ecclesial vocation only after mutual discernment and sufficient formation to be sure the individual will live the life well. Though some might well want to do this, they will fail in what they aspire to. However, the non-canonical eremitical life is still open to these persons and if they should do well at the life in that way, they would, after a number of years, be able to request the church take another look at the case with an eye toward discernment and eventual profession and consecration.
** Ponam in deserto Viam, Congregation for Institutes of Consecrated Life and Societies of Apostolic Life, now Dicastery for Institutes. . .Life.