So what's the conspiracy theory?
the conspiracy theory:
the other options will still be allowed;
this gives Pfizer both the ability to legally mandated (in theory - still needs to see a court), and also distribute experimental drugs at the same time.
it's basically just a bunch of regulatory smoke and mirrors.
follow the money.
FDA gave Pfizer Comirnaty full BLA approval AND extended it's earlier EUA.
They will extend the EUA of other injections and when they want, they will also approve them for general use as BLAs.
So they are playing both games.