There are hard problems in enterprise software that require innovative solutions. For example, data warehousing is crying out for better technology, and as a result, there are a multitude of startups building new technology to compete with the established players. Stream processing is another area with a ton of innovation, as is business intelligence/analytics, virtualization, security, etc. There's tons of innovation around financial services: building systems to facilitate automatic trading systems based on financial models.
One important difference between these markets and the typical consumer startup is that enterprises are inherently more conservative, and for good reason. You need to be able to offer an enterprise a lot of value, in exchange for the inherent risk of going with a startup with unproven technology. That means your value proposition needs to be compelling: you need to solve a real problem, and effectively allow the customer to make more money than they're paying for your software.
Frankly, I think saying "there's not much innovation in enterprise software" just indicates how much of an echo chamber the online startup community is. There is plenty of innovation, it is just rarely described by TC, Om, and the rest.