This is one of the things that impresses me so much with EVE Online - that the economy has stayed as stable as it has. (Sure, there has been some inflation, and some interesting swings at times, but it still fundamentally works.)
Part of that is there is no vendor trash in EVE. Everything is valuable to someone. Items aren't leveled or quality ranked, they have upsides and downsides that you can balance, there are practically no "strictly better" item relationships, even the noobie ships and guns are useful in the late game for low risk travel ships. This item structure, plus PLEX and insurance for money sinks, lets them control inflation and keep the economy healthy.