2. Because the scientists are taking little risk compared to the founders and investors who build the institutions that support their research.
3. Because humans are hard-wired to respect rainmaking and distrust science. Social behavior has been humanity's evolutionary killer app for the last 1500 centuries. Science has existed for maybe 5.
2. The founders are not mediocrities. The people who come in later and use social manipulation to control resources they didn't create are the mediocrities.
3. Interesting and reasonable point.
There are independent research labs and research positions in companies, but in general they are trying to solve business related problems.
"Those mediocrities who get to run the economy" - I'm not sure who you mean exactly, are probably involved in business and thus vvoluntary are interacting with people who value whatever they produce. If you are referring to politicians, well they are adept at spending other peoples money.
However much that helps.