Was it not a requirement that priests had to be the individuals who founded traditional chapels?
Could you clarify the question?
If you are asking how a Chapel, Mission or parish are erected canonically, they are done so by the Ordinary of the Diocese or Territory. So a Bishop or other who is given charge of a territory by the Holy See is the person who erects it. A priest cannot of his own authority “set up shop” without the permission of the Ordinary. Nor can a priest hear confessions, preach, offer a public Mass without faculties given by the local Ordinary or his delegate, except under certain circumstances. Those are primarily that the priest is travelling from a diocese where they have faculties to another place, and are hearing the confessions or offering a private Mass for those who accompany him. Or if someone is in danger of death and another priest is not to be had.
So a priest, even one who is in good standing in his own diocese or order cannot come into another diocese or jurisdiction and just set up a chapel or parish. The SSPX and other groups do that, but even under old Canon Law they should at the very least contact the local pastor or Bishop and inform them that they are in the diocese and seek permission to establish a chapel.
At one point in history here in the USA, Maryland was the only Colony which permitted the public practice of the faith. After a Protestant majority outlawed the Catholic Church from owning property the titles of the Churches were given to groups of laymen, but this was an anomaly and the Ordinary was in the eyes of the Church still the authority that needed to be followed.
For a chapel (or traditional parish) to be brought about, there seem to be a few options:
*]The bishop creates a personal parish for those seeking the Sacraments according to the usus antiquior. This is done by the Ordinary’s own will, or through requests from the traditional community in the Diocese.
*]A priest offers the usus antiquior by his own will, and people come to receive the Sacraments there. Often, in this setting, the traditional community will share space with another community. It can be a tense situation at times, but if everyone’s cordial it can work out.
*]A religious order offers the Sacraments according to the usus antiquior at their own chapel.