You have to take it on a case by case basis though. You can't just have a blanket statement. Chelsea have more academy players in starting elevens than almost every single team in the league the last 5 years. If we had kept every player you criticise the club for selling (and there's context around each one that you should really mention otherwise it comes across as just inventing narratives out of thin air) we'd have a starting 11 of just Cobham players.
In this specific instance, I would say you are just flat out wrong. Chelsea did everything they could to rehabilitate CHO and when he was available for selection, he was always an important part of the rotation. Being in and out of the starting line up does not automatically mean a player is undervalued. If they didn't value him, they would have sold him the second Bayern put that crazy offer on the table. They believed they had something special in him, but the whole thing was unfortunately derailed by a horrible injury.
I feel like instead of coming with the same old attacks on Chelsea's youth integration, it would be nice if you looked at the context of each instance you're discussing and baked that into your overall theory. CHO's situation, for example, is very different from Lewis Hall and Tammy. Loftus-Cheek is very different from Tomori. Mount is very different from Maatsen.