The popular "product" in this space is a cloud based offering with a monthly service cost and a side income based on selling analysis of customer data...

It has good margins and could afford to market heavily and invest in feature development vs anything else. As a result an alternative might well be great for users, great for the world, and also an unsuccessful business.

Doubly so because it's essentially already solved. Setup a standard NVR and portmap it. The marginal gains are just in making it more secure (few care, obviously, or ring wouldn't exit) or a little easier to configure.