Eh. I see your point but feel like that type of belief ('need an ace for the playoffs') is more selective memory than actually borne out in reality. The Orioles best pitcher that year threw 168 innings, 8.96 K/9, 2.35 BB/9, 2.83/3.77/3.27/3.53 ERA/xERA/FIP/xFIP, 3.8 fWAR. The best Rangers pitcher threw 144 innings, 8.25 K/9, 2.94 BB/9, 3.63/3.98/3.88/3.96. Yes, obviously there's a reputational difference between Kyle Bradish and Nate Eovaldi, but going into the post season there's not really a reason to think they were an ace short vs the eventual champions.
More importantly, typically if you go down the thought process of wanting/needing an ace, there's like 6-8 of them in baseball in general and almost all of them aren't anywhere near available, so I'm just not going to lose sleep over it. Hopefully it's Horton in a year or two, until then we just have to hope that Shota is a big game pitcher and the other guys are healthy come the fall.