if any of these startups succeed, my condolences to the engineers who get hired afterwards and are stuck bugfixing
This is any successful startup - you don't succeed by making a perfect product, you succeed by making a buggy mess that's enough to convince both investors and more importantly customers that there's potential... That means you need to rebuild from scratch in years 2-4 anyway, so frankly for the engineers who are coming in then, there's little to no difference
I personally haven't bought anything from Amazon for years now (or really anywhere online, I think maybe 8 things in the past year?), issue is even within the last week I've spent hundreds if not thousands on AWS through work... Sure it's not me paying, but it's also pretty hard for me to not to given they have such a monopoly