Truth is most youth players don’t make it and if you end up on loan then you’ve probably already failed.
Take Liverpool for example. Sterling and Alexander Arnold never needed a loan whereas the likes of Woodburn and soon to be Brewster will end up nowhere near the first team despite the hype.
There are demonstrably proven ways to increase your chances of generating either profit or a first team player, and one of the biggest is getting them minutes as soon as you can as often as you can.
Some players don't need a loan no, but part of that is how modern football is and how insanely powerful the prem is, you need to be an extremely powerful athlete to hold your own, most players even very good ones aren't that at 19.
Youth players make the balance sheet look a lot healthier as well as any sales are just profit profit profit.
Chelsea's business model for years has been to run the club at a crazy amount of loss, but make it up in player sales and the academy has been a huge part of that.