With all due respect; your point here is pretty stupid. Ortiz is the first guy to maintain elite performance at that high an age since who? Barry Bonds? To pretend that this is some sort of expected outcome at this point is lunacy; it is beyond extremely unlikely...and we've got a guy on our own roster (Jose Bautista?) who proves that, with prime Bautista actually being a better hitter than Encarnacion. The only other name that people can bring up is Jim Thome, and in reality Thome is a guy who clearly regressed after age 35/36 despite ONE fluke season in 2010 (age 39) wherein he managed to re-find his elite hitting albeit in a season wherein he only played in 108 games. To use David Ortiz as some sort of "expectation" of Encarnacion's future outlook is beyond foolish. Even Boston knew that Ortiz's elite hitting performance relative to his age was unlikely, which is why he's been playing on 1-2 year contracts since ~2012.
The reality about Encarnacion's season this year is that metrically it was actually the worst hitting season he's had since he officially broke out in 2011. The only reason why it looks like he's been as good as in previous years is because he managed to play in more games this past season than in any of those previous years. More at bats = more standard counting stats (RBI's, HR's, etc). In reality his strikeout rate jumped ~5% this year and his wRC+ dropped about ~15 points. There is no reason to expect that Encarnacion from ages ~34-38+ is going to somehow manage to stay healthier than he did from ~29-33.