I think they feel they have had a chance to go the World Series for a few years in a row, now- unlike us. They actually went in 2020.
When they trade away good players, especially mid-season, I think they do so, thinking they are getting someone who will be helpful in a few years, and as they do that, they are calling up someone they traded for a few years ago. It's a replenishing cycle that works, and it could work for big spending teams, too, but only for players they don't intend to extend- something the Rays never do, unless they lock a kid up way before arb years.
The Rays are trying hard to win a ring, within the budgetary confinces their owner places on the GM. They have found a way to be pretty highly competitive for many years in a row.
They got their initial start at measured success, by getting several high draft picks in the mid 2000's, but since then they have worked the system in their favor. They used to hoard comp picks, but when that went away, they changed, yet again. They rely on great scouting of ML talent and knowing when someone is about to have a career year, or knowing a tweak that will improve someone that may have been like a journeyman their whole career.
They have had 3 losing seasons since 2007 (one was 80-82), and have never finished last since then.
Since 2009, they have had no winning seasons' winning percent below .556.
Since 2017, they finished 3, 3, 2, 1, 1 and are currently in 2nd in a very tough division.
To do this on a restricted budget is simply amazing, and it's no mistake 3 people from their system are now GMs on other teams (LAD, HOU & BOS).