Ping
“...more SSPX priest[s] should be invited...”
Yeah.
Invited, great. But growth in the number of SSPX priests, sufficient to take advantage of such an invitation, or, put another way, to supply such a dire need, can take place only over time, and gradually.
Moreover, though diocesan priests with strong aptitude and experience celebrating the Latin Mass may get such a notion, the SSPX focuses more or less exclusively on the proper development and formation of its own seminarians.
In other words, with rare exceptions, the Society is not set up to accept or absorb men ordained elsewhere.