You develop, get copied, develop, get copied, copied copied, what's the point?
Because it drives development.
There are many reasons why Apple, Microsoft, Alphabet, Nestle, Mars, Pfizer and other big corporations stay in their niche and don't interrupt in small businesses.
Exactly. So there is far more nuance to it than your initial claim that someone rich can just clone your product and drive you out of business. If that was the case then Trezor wouldn't exist, Passport wouldn't exist, BitBox wouldn't exist. All the best pieces of software for using bitcoin - Electrum, Sparrow, Bisq, Robosats, etc. - are open source, and are yet to be cloned and driven out by a rich competitor. The same is true for bitcoin itself.