Those aren't just competitive spaces -- those are almost the paradigmatic examples of concepts that have repeatedly failed over the past two decades to demonstr

Those aren't just competitive spaces -- those are almost the paradigmatic examples of concepts that have repeatedly failed over the past two decades to demonstrate business value, but that startups and investors keep returning to like Kipling's burnt fool. Those are concepts that are highly competitive because they have near-zero barriers to entry, while the underlying markets are themselves highly fragmented (significantly driving up your acquisition costs), highly competitive (meaning that there isn't much revenue to share with your startup), and already using multiple capture channels for their customers (meaning that you are unlikely to provide killer value to them). But for some reason -- I have my own theories there -- there's always some concept in those spaces getting funded, so they seem more greenfield than they are.