There's an interesting point to be made about B2C vs. B2B products.

There's a thesis out there, that in order to test the market you can put up a simple website adverstising your yet-to-be-made product and see if you get any subscribers. I feel like this applies to B2C products and low ticket B2B products (i.e. $10 per user per month).

The playing field for a serious B2B product is very different and the MVP needs to be in good shape in order to win and keep clients.