A couple things since I still think Cade Horton is easily the best pitching prospect in the org and a top 100 prospect in baseball (especially since this season didn't result in him having to have surgery and the Cubs believe his velo drop off in AAA was related to mechanics):
1) There are only 3 pitchers this year who will break 200 IP in the big leagues. In 2014, there were 34 pitchers that hit or surpassed 200. The 34th most IP this year is 173.2 (admittedly, most teams have 3 more games so 34th might bump up a bit). Clearly, more and more young SP now build up their innings in their first few years in the majors.
2) Pitching injuries are rampant in the minors and majors and a lost year of development is no longer a death knell to a prospect's chance of being a major league SP. Check out the sheer number of pitching injuries the best pitching development teams (Dodgers, Guardians, Rays) have and you'll see a chunk of these prospects pop back up healthy a year or so later and eventually turn into viable big league starters (yes, some like Dustin May are probably toast after multiple injuries). Justin Steele's development is a perfect example of this. It's just par for the course with pitching development in the 2020s, when teams value velocity and spin. The key is to have a lot of pitching prospects and realize pitching development is even less linear than hitting development due to the additional injuries and innings ramp-ups.
** That said, the Cubs limit the innings of their A-ball pitchers more than most orgs (since their SPs only pitch once a week in A-ball and are still capped around 60-75 pitches/week) and there's no evidence the amount they baby (for a lack of a better word) their pitchers actually protects them health-wise and I'd assume the lack of innings they get in A-ball hampers their development.