You're right. I will never question Pfizer again. There could be infinite mutations of the virus moving forward which would impact the weight of their claims.
I didn't say you, nor myself or anyone else, shouldn't question them, just that they haven't been incorrect in this instance as you've suggested. I'm not sure why your snark is needed in your multiple responses here.
They claimed it was 90% effective in the (time limited) study which they performed.
It’s fair that you might have misinterpreted that as meaning it will be 90% effective. Especially if you don’t know how viruses work, but that’s not what was actually claimed.