You left out "be first" which is an advantage that is much harder to find these days, which creates even more pressure to differentiate by other means, legal or otherwise.
VRBO was loooong before AirBnB. AirBnB reduced friction by handing the payments and provided social mechanisms for buyers and sellers to vet each other, among other things. In the days before AirBnB I remember booking an apartment in Paris by sending half the payment by wire transfer and the other half in cash on arrival. The apartment was great and the host even better, but the payment was painful, and something very few of my friends and family would have done. AirBnB made it as easy as booking a hotel, and that made a huge difference.
AirBnb is the canonical example. They weren't first, so they built a business around doing something that in most places is illegal, and it caught on in a big way.
I'm not discounting their UX, I'm sure it was a big part of their growth.
As an aside, "be second" isn't bad, either. There was an article about European businesses copying successful American startups. Why innovate when you can profit/learn from others' ideas?
Or American startups like uber copying successful European startups like blablacar.
You mean like google that was there before altavista? Or Facebook before MySpace?
I think these examples are dated and don't hold up in the modern, mature tech ecosystem. Facebook bought Instagram and copied Snapchat's main features to put big pressure on them. It's not as easy to overthrow the king as it used to be.
If you consider IG to be one of the newer example than also consider that IG copied most features from “first mover” Snapchat