Many years ago I remember thinking that a team ought to try a 3-3-3 approach. Get three guys to throw three innings apiece. Heck, you could have three sets of those guys on your staff and pitch every other game that way. Anyway, it was a notion no one took seriously and that's probably good.
Despite the disappearance of the complete game every team still wants a rotation of five Max Scherzers. Of course there is only one of him and maybe a handful of guys just as good as him. There aren't 150, that's for sure. Thus we have killer bullpens and five-inning starters.