Honestly, I think that the main reason they didn’t bother overturning is because in addition to the initial ruling they also blew the play dead prior to the recovery by GB.

So even if they did agree that it was a fumble, the result would have still been Steelers maintaining possession at the spot of the fumble, since I believe if they blow a play dead on a loose ball then the original team keeps it.

There is an exception where the opposing team recovers immediately after the inadvertent whistle, however I’m not sure how they govern the immediacy of it. My understanding was that it had to be like one continuous motion, while in this case Gary took a second after the ball was called dead before reaching down and picking it up, so I’m not sure this would have applied. I could be entirely wrong though.

What’s not in question is that even if they ruled GB ball, they definitely couldn’t advance it further. So definitely no touchdown.

I think in this case, rather than getting into that entire bag of worms caused by them admitting they got the initial call on the field wrong, they just decided to double down on letting the original call stand.

Blah