If something else gets an EUA at this point, it would have to have nothing comparable and solve a critical issue in the US. We have now considerable evidence that multiple different vaccines are highly effective at training your body to defend itself against COVID. Therefore, your statement implies this is new wonder drug which does better. So, it must both reverse permanent damage and be almost 100% effective at stopping and curing COVID. And it must both be something we've always known about and is something we have never seen before.
Clearly this wasn't true 9-12 months ago before the vaccine trials finished, so this would have been quite different then, but I digress: we probably don't have a time machine (or do we? Pfizer et al. might stand to lose a great deal if we do).
And, yes, if somehow all that happened, I think we'd all be very happy, even Pfizer et al. Also very confused. But happy.