What I see time and time again with teams and people prelaunch is a lack of a catalyst to ship their MVP. I've met many people who have an idea and their MVP is 95% complete. Then things stall and feature creep sets in for three reasons:
1) Your MVP will, by design, have technical debt. No one likes debt.
2) Releasing means a shift from being a dev/engineer to being a marketer and building the company that builds the product. And you do this while also working on your technical debt. If your sales stall, then you are stuck in "should I spend more money on time on marketing" hell.
3) Anyone who can build something people want and create an MVP has numerous alternatives for certain income.
So as much as I'd like to ship my MVP next month I procrastinate since I am also a consultant who bills at good hourly rate and I can just do that instead. Good isn't just the enemy of great. Good is also a great hedge against the time waste of building a business that is no fun to operate and isn't profitable which is why many MVPs never ship.
Edit: typos, clarity