You don't even have to look far for elite hitters that fell off a cliff in their mid 30s. Former Jays:
Bautista, Donaldson, EE- all were basically done at 36 and had much better bodies, work ethic than Vladdy.
Ryan Howard was cooked at 32 and the list goes on and on.
Also you are forecasting in the future, 5-8 years from now the league is only going to get more athletic, younger etc... Guys are going to be throwing harder and being 33-35 then might be what 36-38 is now.