Ahead of today's derby, Moyes was asked about Liverpool's record £446m spend this summer.
Moyes said: “You have to earn the right. You have to win and be in the big competitions which make the money.
“I found at West Ham that three years in Europe allowed us to spend money, allowed us to bring money in and upped the spending. From that point of view, Liverpool are entitled to do that.
“I heard Arne (Slot) defending himself and he’s brought in a lot of money as well, which he rightly has done. But I still think they’ve spent more on one player than we’ve spent on the whole squad.
“It gives you a realism over where the game is and where the clubs are. I need to try and shorten the gulf between the two clubs.
“At the moment, Liverpool are champions and are probably favourites, if not second favourites, for the Champions League. We’re not, we’re Everton who have had three or four difficult seasons and we’re just beginning to rebuild and trying to bridge that gap is quite difficult to do.”
Moyes added: “Obviously they’ve bought in a lot of really good players. Over recent years, Jurgen Klopp’s teams have been fantastic, and I think Arne Slot has come in and done a brilliant job for his club in the one year he’s been here.
“They’ve gone out and bought some real top players which has strengthened them again. So, they’ve looked to improve again, but I think we’ve improved as well and I think from my point of view, I have to look at us and what we’re doing and I want us to keep improving and get better if we can.”