I think what he's saying is that, in general, sometimes, players need time to work through their inconsistencies. Not all the time of course, but sometimes it's worth sticking with a player. Cucurella is a prime example of this because the entire Chelsea fanbase was pretty much ready to sell him at a huge loss just to get rid of him and Chelsea were seemingly ready to loan him to United last winter. So he's come from the depth of football hell and resurrected his career at Chelsea. I don't really think the likes of Caicedo and Jackson belong in a conversation like this because they were actually playing pretty well last season, they just weren't getting the flowers they deserved, and the likes of Madueke and Colwill had up and down seasons but they weren't outright bad like Cucurella was.
You are right though, that although I'm glad we finally look like we can put some consistent results together, I'm not a fan of the process it took to get here. There was no need to sign 40 players in 2 years. Just on the surface that's absurdly ridiculous, even before you get to the practical and logistical issues a squad of that size created. I read in the Guardian the other day that there was approx £500m worth of talent signed by Clearlake (24 players) that have started fewer than 3 games for us this season. Obviously some of that is kids like Estevao and Paez who legally cannot join Chelsea until 2025 but most of them are players that will never ever sniff the first team at Chelsea.
So yeah, Maresca deserves a lot of praise. He's managed to quieten all the noise around the club by just winning matches but I don't think anybody should be looking at the process Clearlake took to get here with envy or ideas that should be copied.