For those of us not working on cat photo sharing products for the ever shifting consumer market there is considerably less luck, throwing random stuff at the wall, and pivoting involved. B2B SaaS is pretty nice. Join us on the dark side :)
The big question is: how do you discover and identify a good b2b problem that needs solving in the first place.
This doesn't mean you don't iterate. A lot of the lean startup stuff is still useful to us (a/b testing for more focused UI etc.). But generally speaking, we know where the product is going, and our customers' needs, often better than them.