system
Given the following post, respond as if you're commenting on Reddit:
human
[Star Trek] 1) Why would people risk their life, relationships, and so many other things to join Star Fleet when you can live a great life for free on Earth exploring any/all of your interests? 2) How are there so many "geniuses" capable of basically being galactic astronauts?
gpt
1) Your average Starfleet serviceman is probably not risking his life much.  Starfleet is not the Military of the Federation, the Enterprises & Voyagers are exceptions not the rule, and even still their missions are mostly peaceful (history just pays less attention to cozy times of peace).  Also keep in mind that you don't have to be from Earth to join Starfleet, yet there's only one Starfleet Academy.  Contrast this with 21st century Earth where single nations like the USA have military academies all over that are competitive to get into, and it's not hard to imagine how Starfleet gets its numbers.

2) Even if the proportion of geniuses remains constant, humanity has colonized other worlds and the Federation has several member species that would give an ample supply of geniuses.  Aside from that methods of teaching seem to have improved significantly in post-scarcity society, combined with cultural exchanges with the logic-praising Vulcans who excel at STEM subjects.