Then the responses to that is Staubach and Aikman both had better coaching, better running games, better defenses who could stop the run and didn't play in an era where most of your best players didn't leave due to Free Agency, especially Staubach.
Would anyone disagree with any of those facts?
Staubach played in the era where WRs and QBs were allowed to be mugged, and OL could not use their hands, making his accomplishments even more incredible. He won his rings with two completely different teams and was reknowned for playing his best when the chips were down. That is why he is widely considered a top 50 player all time. The comparison between him and any modern player is a stretch though I do think Mahomes is the best i have ever seen.
As for Aikman he had a better line, a better RB, he had very good receivers, most importantly a coach who demanded excellence. The passing game rules were closer to todays but you could still unload (spearing) on the QB. Aikman took a shot his rookie year from Anthony Bell that would have ended some careers. Did Aikman have a great team, yep. Many players have great teams and don't cash in. Troy lead the team to three SB wins.
The difference is Staubach and Aikman demanded excellence from themselves and their teammates. That is why they have 25 playoff wins between them and five Lombardis. When the lights were bright they showed up and played lights out. They didn't disappear for half's of games or not show up at all. And I certainly don't remember players talking trash about them when they ex Cowboys, or their relatives talking trash as current Cowboys. For many of us we are way past stats and excuses. At 2 and 5 in the playoffs it is time to try something new. And for the record I feel the exact same about Romo.