It seems to me that this misreads an essentially permissive enactment. The first principle of Summorum Pontificum is that the older form of the Roman Rite was never abrogated and was therefore, in principle, always legitimate. As Article 1 states:
"It is, therefore, permissible to celebrate the Sacrifice of the Mass following the typical edition of the Roman Missal promulgated by Bl. John XXIII in 1962 and never abrogated, as an extraordinary form of the Liturgy of the Church."The previous conditions under which this form of the rite could be used are then substituted with conditions that give greater freedom to priests and laity.
There are a couple of restrictive conditions: the priest must be idoneus; only one such Mass is allowed in an ordinary parish on days of precept. There is no stipulation that the priest must wait for a group to ask him - the point is that if a group should ask, the pastor must "willingly accept their requests" and if he won't, they may have recourse to the Ordinary.
Summorum Pontificum is not saying "You may celebrate the older form of the Mass if and only if these conditions apply" but rather "you ought to celebrate the older form of the Mass if these conditions apply". Since the general principle is that the older form is legitimate, not harmful or forbidden, should be preserved as part of the riches of the Church and remains noble and great for us too, there may be many other circumstances in which it is pastorally desirable, in the judgement of the pastor, to celebrate this form of the Mass.
And, of course, the norms do apply principally to pastors. As the Holy Father says in his accompanying letter:
"The present Norms are also meant to free Bishops from constantly having to evaluate anew how they are to respond to various situations."