It's never that simple, that's not the only possible endgame.

We have seen plenty of examples in other industries where you can never really stop investing a ton on R&D with diminishing returns (like in semiconductors or pharma), because the moment you stop newcomers overtake you.

Or the whole thing becomes a commodity with lots of competitors, where technological advantage is overtaken by marketing as the dominant force.

Or you really are left as the only player alive, but you realise that the market cannot absorb higher prices for your product by then, they prefer just not to buy it. Perhaps you are the only player alive because the business has become so low-margin that everyone else has abandoned it intentionally.

That Silicon Valley pitch you are echoing rarely works out as advertised, even for the winners.

  We have seen plenty of examples in other industries where you can never really stop investing a ton on R&D with diminishing returns (like in semiconductors or pharma), because the moment you stop newcomers overtake you.

I think you're proving my point. Eventually, R&D heavy industries almost always become a monopoly or duopoly. Small/losing players can't keep up and drop out or acquired.