I think we all share the same concern. I am told to lauch by everybody (even here) but I can't until I have at least fixed the MVP to fit my minimal standards.

It is hard to explain but you've nailed it. In development, you are alive and can fix things. I do not want things to go wrong for my users.

By myself, I have a lot of leeway. There are many things I can tolerate, and I often strive for "good enough"

But I can't do that with future users involved, even if they don't exist yet. Because they will trust me to deliver a good product, and I want to be worthy of their trust.

To add my two cents: I guess that people do not fear getting wiped out as in being killed because the product was bad.

When launching, the dreams / expectations that fueled the development will get "reality-checked". The initial dream comes from the heart, so when the launch fails, people fear that their core identity is being attacked. You could call that the negative side (from a personal pov) of external validation.