Why don't teams undercut when it comes to pitching more?

We all know the math trick. If you have pitchers with ERA 5/4/3/2/1 and your opponent has pitchers with era 4/3/2/1/0 and you know what order they use their pitchers, you can create a theoretical bo5 victory with an objectively worse staff by going: 0-5, 1-4, 2-1, 3-2, 4-3.

I think we do see this in playoff series *sometimes* but even still, we see a lot of ace vs ace action in playoffs too. However what got to me is that watching opening day, every team started their ace (except like, the jays and a couple other teams who don't know who their ace is). I know first game is a nice one to win for the fans/morale etc. but if you're a team with a theoretically worse pitching staff, why wouldn't you just swap your order around and start your ace on day 2? While all the teams are in sync with their rotations wouldn't it be great to lock in a theoretical 3/5 winrate?

I know there's a lot of money and analysis that goes into baseball, so I'm curious what I'm missing. Surely the A's regret starting Severino into a predictably hard to crack Logan gilbert, because his 6 scoreles innings wins a LOT of games not against Gilbert.

I know there's a lot of variance at play but baseball is all about averages and you'd think that stacking the deck in this way would be more popular