We will sell any player if it makes good business sense to do so. I think the model has changed now after the failure of the Walsh/Koeman regime. Invest in younger players so that the potential for sell-on is big. If you're signing a player 26 or over, make sure the player is free/on a low transfer fee to help negate the fact that their sell-on value will be low. It's not rocket science and it's what a lot of clubs preach, but I think we will see more of this happen, where we rely on player trading more - simply because it's a good income stream if you get it right. If we have more confidence in the DoF to bring good players in, it becomes less of a problem if you lose the ones you perceive as your top players. The only way this changes is if we become CL regulars down the line (and given UEFA are closing the shop on that, it's hard to see happening at all).
Richarlison was a very smart signing by Brands and Silva and I'm sure we will make a very tidy profit on him at some point. We will then move onto the next one. No biggie.