Yeah, I don’t think you’ve got all the facts to be making that claim.
Here is a story about Keri Hehn, who can be described as an “Olympic hopeful”. It talks a bit about who gets funded in swimming, how much money they get for it.
Note, please, how except for a very few swimmers, it pretty much says exactly the opposite of what you are claiming is the case.
There is a track and field circuit in Europe in the summer that pays pretty big money and attracts athletes from all over the world. The NBC commentators made frequent reference to the US athletes “competing in Europe” and they were referring to these events. The AF Golden League is an example.