No that's not what was asked. If it was, I'd agree with you. DT is probably the only position where the 2015 Bills are better. The 90's Bills were better at literally all 11 positions on offense.
I interpret the question as "does Jim Kelly in his prime, transported to today win a SB with this supporting cast?" and in the FA era, the answer is yes or at least maybe. The talent in the league is much more spread out now than back then when a few teams had all the talent.
Another way to understand it - do the 2014/15 Bills with Aaron Rodgers at QB win a SB? Not a given, but they would certainly be live.
We just watched two very flawed teams compete for the title this year.