A big part of the US VC operating model these days seems to be just rebuilding existing products with slight changes, then pushing all of their other startups to use that version of it. This is only going to accelerate with AI. Why pay some company you don't own to do thing for you, when you can just copy the company (maybe even improve it in some ways), seed it with with your large existing user base, then have it do the thing for you (while also generating profit from other customers and rapidly scaling in users and valuation itself).
The reality is most of what most tech startups are doing is not actually hard and has no moat. The moat is in getting users/customers - connections/marketing/sales - product quality also matters of course, but there are plenty hyperscaler unicorns who's product is dogshit and vice versa.