I think there are more frontiers than we are generally aware of but for sure the lowest hanging fruit are already picked. Frontiers generally have to be invent

I think there are more frontiers than we are generally aware of but for sure the lowest hanging fruit are already picked. Frontiers generally have to be invented by people willing to go out into the unknown, and I guess the willingness to try completely new things with no obvious benefit is what is missing. Startups are everywhere for those whose ambition is primarily "become wealthy", but most are funded and investors want a credible route to market. The clearest image that portrays this for me is the 60s scifi images where people were imagining robot butlers, flying cars and cities on the moon and under the sea, all by the year 2000. It really captures what's missing nowadays, and what Elon represents to a lot of people.