In many fields doing science requires a team and equipment, and in all fields doing science requires being able to sustain yourself while spending most of your

In many fields doing science requires a team and equipment, and in all fields doing science requires being able to sustain yourself while spending most of your time on science. All of that requires funding, which almost universally (not limited to American higher Ed system) requires demonstrating that your science is accepted by being published in respected peer-reviewed venues, and if it's only self-published then it's considered not worthy (and there indeed is a big correlation for that) and results in you being denied the means to continue to do science. In essence, science gets validated by being published in selective places which demonstrably filter out most of the chaff (and a lot of science-like products should get filtered out - even in this domain attention is scarcer than content, so almost nobody wants to read things that haven't passed a certain filter) and if something gets published in a less selective venue, the general assumption (again, strongly correlated with reality) is that it wasn't good enough to get published in a better one. Technically, of course, you can be a scientist without involving yourself with all that, if you're independently wealthy and/or doing it as a hobby in addition to your main job. Science used to be done that way (e.g. by bored educated aristocrats), but I think we have a strong consensus that the world would be worse than the current situation if there would be a de facto limitation to doing science only by those who can self-fund it.