Your argument is just poor. You're stating that Austin, a man who hasn't wrestled in years because of injury, can't fight Brock in one last match. Yet, he's maintained his health and had time to rest.
But, somehow, you feel that taker... A guys who has years of old age over Austin and still a damaged body, can just hold a match better than Austin?
Taker can basically take bumps and sometimes build a head of steam and hit some big move. He basically takes a beating. Something that lots of people can do. His name is why he sells PPV.
To an extent, in all fairness, I see your point, but when Brock is about to fight a 52 year old man in one of the most brutal matches in WWE history, your point sucks. And, WWE won't let Austin wrestle unless he can do some good stuff and take hits. So if they go this route, he's obviously fine.