Couldn't agree more - inheritance chains and heavily stateful instruction environments are the number one blocker to eventually decoupling a monolith. The "enterprise" code style is absolutely what you need to avoid in a startup.
Absolutely agreed, where Enterprise === "making a profit"
If you avoid what you listed in actual software, you'll be left with a mess they will take years and tons of money to fix.
Yes, but if you don't avoid it, you might never get off the ground to the point where you have years of time and tons of money in the first place.
I guess it depends on the viewpoint. Yours sounds valid. Mine comes from the occasional fixing people's messes. But I agree with you, some product is better than no product in most cases.
I have a lot of career experience dealing with legacy software. I feel that pain intensely. But still... a working product with bugs and flaws is better than a not-working product that is elegantly built. Or half-built.