The three players you mention are all low cost / high potential players that we bought and then sold on for a decent profit. Add into that the likes of Braithwaite, DCL, Holgate and then others in the wings such as Ben Gibson. Even the big money signing of Richarlison has been a wise investment under the model you describe.
Trouble is the whole shebang is a little more complicated than just doing that. It's not a new fangled model that nobody has ever thought of. A huge part of RBL's rise into the Bundesliga has been their huge spending power in comparison to other lower league German sides due to them binning off the traditional ownership structure within German football.
It's easy to look at their success from a distance and compare to Evertons failures. Do you think Everton signing Lookman for £10M from Charlton and flogging the bit part sulker that he was to RBL for £18M where he has done nothing since is a good example of RBL working that model?
Or do you just mention their successes in comparison to Everton's failures and vice versa ignore their failures and ignore Everton's successful applications of this "model"?
I didn't particularly go into any detail because frankly I can't be arsed.