There's plenty of stuff that i've made that's useful in the form of an inelegant API that i don't mind using. But to build a polished product with documentation, a marketable presentation, analyze what you offer that the competition does not, getting people interested, blogging about it, is quite a lot more perspiration.
Writing a useful MVP is necessary, but often the easiest part. Most ideas dont fall under "if you build it and they will come".
The SaaS and subscription model evens out the revenue spikes, but you still have to make the sales.
A salesman, I am not. I suppose I should learn how to do it, but I don't have much passion for the sales side of business.