I did see an impossible meatloaf in a grocery store, and it looks like their website is showing ground beef. So it looks like they are slowly branching out into other products.
Beyond seems to be moving into that space, and Impossible is giving them the moment. Whether (or if) Impossible can recapture that market segment remains to be seen.
Possible but seems pretty unlikely. Also, I don't think they'd be allowed to use Impossible's trademark in that case.
I feel like the GP must be misremembering.
Edit: the meatloaf was served by the deli premade, it wasn't sold individually packaged.