Where did I say stop signing young players?
I said to have a balance in the squad. Having a good mix of older experienced players, players in their prime, players coming into their prime and the younger ones with potential. Nowhere did I exclude any section of the football player timeline.
When I see a signing for Everton, I don't consider how much they cost, how much they are earning or how much we might sell them for. I consider, can they win us something, can they add to what we have on the pitch. Don't even consider their age, some of our best signings in my lifetime have been the older players.
As mentioned, it is imperative that a squad has a good balance. You mention Brentford, they bought Henderson. There is your balance, they thought that he could add something to the squad, with no consideration for any sell on fee, it is likely that he will retire there, so they get nothing back. We have done the same last summer, we bought potential, players in their prime years and a older more experienced player (If you can consider Grealish in that category).
At this time, I think we do have a good balance. We can argue whether Moyes is using the squad in a balanced way, but there is a good age range there, with differing levels of experience hopefully helping out the non experienced.