To your first question, I believe they somewhat already have. If you look purely at the numbers, I believe they already lead the world in newly published AI research or are quite close to that. In my opinion, its because the K-12 education system is much more tech focused there, and until the US competes at that level of education as well (which seems somewhat unlikely, considering the state of public education in the US government), we will surely be not just outpaced, but completely dominated in the next few decades. Also at the doctoral level at many Ivy+ schools, almost half of PhDs in tech come from international students, so you can draw whatever conclusions you'd like from that.
To your second question, none of them. They will likely purchase another company doing such h things. One thing that we have to realize is that cutting-edge B2C AI generally doesn't usually make money in short term timelines. Companies that do often end up being unicorns or acquired by one. If you were to take a look at how FAANG companies make the majority of their money, I would bet a lot of money that its not the jaw dropping consumer AI systems. From the B2B sense, however, probably Amazon, as they dominate the B2B computing market already.
The third question: hard work rarely yields personal financial success. This may be a jaded opinion, but the majority of wealth made in the US isn't made by the hard work of the person who benefits.
The most profound book that I've read in the past year is a book of poetry, called the sun and her flowers, by Rupi Kaur. For me, poetry helps me find solace and meaning, and speaks when I cannot come up with words myself. Lastly, the startup that excites me the most is the one I'm working on in secret.