Yes, this is true for most of the players who end up at Atletico. This is Simeone's system - it doesn't produce stars, everyone has to be a cog in the system. But there is another pattern here - Atletico gets players who are ready for such a development in advance and either they know that they have reached their ceiling or they don't see themselves outside the system from the start. So you can't say that Atletico ruins players (like United haha), initially it's mutual interest.
Atletico Madrid is very different from Manchester United. Diego Simeone gets to know the players and signs players who can contribute. This fosters good team chemistry. Atletico Madrid is known as a very good team in the Spanish league. One of the main reasons for this is Diego Simeone, who has been managing the team for a long time. I really like his tactics. He likes to dictate the game with savvy transfers and logical moves. His biggest misfortune is that he's based in the same country as two world giants, Barcelona and Real Madrid. Despite this, he's a manager who has won championships in the past. Therefore, I completely understand Atletico Madrid's continued desire for him as manager.
This is a moot point. Simeone has been at Atletico for 14 years. During these years he has become the highest paid coach in the world, but he has won only two La Liga titles + two minor European Cups (UEFA Cup). At the same time, Atletico's squad is not much worse than that of a couple of competitors, at least Atletico is much closer to them than any of the remaining teams to Atletico. It seems to me that globally Simeone has achieved only what he was supposed to achieve in such conditions + if you take the last few years, the team is very bad, if he can’t at least return to the previous level, he should leave.