The problem is that in many business domains, the absolute minimal viable product, or even a customer-worthy demo, is a 6 month long, 10-15 person project. If the market already has complete solutions available, releasing an app which does 5% of what other apps do + 1% that's different is simply not viable, and is likely to help you never get a second look.
Well, yes, kinda, sorta.
If you go into a market that already has a complete solution available, and that solution works well, you need to be at least as good as competitors.
But the way you go into a market is by figuring out what doesn't work. What is an unaddressed pain point. This is a hard thing to do by definition (that's why the payout of being successful at it is so big), but if you manage to do that, you don't need 10-15 persons for an MVP... in fact I'd argue you actually can't truly do an MVP if you have a 15-persons team. You need the large team to expand the MVP, but to identify it/ have a customer-worthy demo, the 15 people will just get in your way.
The view in my company at least is that even if you have a strong differentiator feature, if you don't have more or less all of the baseline features that all the established products are doing well, people will take a look at your MVP because they like your killer feature, try to use it, find out that it doesn't do all the things they need, and never look at it again, even if you do fill those features later on.
That can't be true or no startup would ever get off the ground. Just look at any Adobe competitor and see if they started fully featured (most actually brag about their lack of features compared with Adobe products)
The more likely explanation is that your "strong differentiator feature" is not really as strong as you'd wish it was.
