I'm working on a DITA (to PDF) renderer [1] based on rinohtype [2]. About a year ago I was in a startup coaching project. I was advised to put out an MVP ASAP. Since then, I've worked full-time on the project and only now I'm releasing what I believe is an MVP. One year ago, my product was functional, but it didn't allow easily styling the output PDF. I believe this is the feature that differentiates it with the competition. I feel that, without this feature in place, my product wouldn't offer anything interesing.
I could have also released an "MVP" much earlier, but say it couldn't render tables. Who would've taken it seriously then? Even if I added this feature at a later point, how many of the people that tried the first version would bother checking it out again?
For some (new) markets, I'm sure you could crank out an MVP in a month. But for existing markets, there's the established competition that sets the bar, no?
[1] http://www.opqode.com/rinoh [2] http://www.mos6581.org/rinohtype/