That's not Thiel's argument at all. His argument is that the most innovative companies tend to become monopolies.
However monopolies are not always due to innovation, nor our monopolies inefficient. As you mentioned, it's a function of things that repeat, but also due to stronger players that gobble up less efficient and/or innovative firms.
I would read between the lines. Business history is indeed difficult.
First, I replied to a comment. The majority of your points should be directed there. Second, your point about monopolies or why they happen is just uninteresting (the question of "always" is not something that can be answered). Third, your point about the most innovative companies tending to become monopolies is wrong...I am not sure how little you have to know to think this but it is certainly very minimal. The historical evidence is that industries consolidate down to a few large companies, not that they become monopolies. Fourth, again, I repeat what I said about ahistorical nonsense. Neither in theory or reality is monopoly a natural consequence of capitalism. Fifth, most monopolies that have existed in reality, by number, are not privately-owned, they are not innovative. There is a fairly obvious inverse correlation between monopoly and innovation (again though, the issue that is confusing you is thinking that innovation -> monopoly...this isn't a thing).
Thiel’s point is on the extreme end if you have hyper-competition, firms will have no money leftover to invest in moonshots (self driving cars, cloud computing, etc. ) instead they focus on pure survival.
I don’t see how a company that’s in a life or death struggle could pour hundreds of millions/billions of dollars into R&D but perhaps I’m missing something
However monopolies are not always due to innovation, nor our monopolies inefficient. As you mentioned, it's a function of things that repeat, but also due to stronger players that gobble up less efficient and/or innovative firms.
I would read between the lines. Business history is indeed difficult.