In my opinion, apart from investing in better players, they also take care of or facilitate their academy players so that young players can easily enter the squad, currently they rarely promote academy players and in my opinion they should focus on that because we know that young players from Spain are currently quite good in their development if so they will be able to make that money without having to waste money buying many players and spending it on things that should not be.
This is too long a path that Real cannot afford, they need results now, so they give players from their academy a chance to play somewhere on loan, get some experience, and whoever can prove themselves will get a chance to play in the main team. The most important thing for Real is the result, and for this they will attract the best players they need. If they need a reliable defender now, then I doubt that they can get him from their academy.