- ERP ssystems are impossible to understand for the people that work with them, and require an army of highly paid consultants just to get it up and running.
- financial software for large companies doesn't allow managers to see numbers in real-time, is difficult to get numbers in and out of, and hard to use.
- HR software for managing people, their interests, knowledge, track record, etc. in large companies.
These are just a few examples off the top of my head, I'm sure there are many more.
The advantage of B2B software is that you have a very good income model. A SAP ERP system for a company with 1000 employees runs into the millions. There are customers out there willing to pay you by the bucketload if you can make something that doesn't suck. And most of what is on the market today sucks badly.
This is an industry that has been resting on its laurels for many years, and is ready to be picked off by nimble competitors.