Frankly, I just disagree:
* Pricing is mostly irrelevant at the beginning. Even Google didn't figure out its business model and pricing long after they were created. The only thing that matter initially is to gradually converge toward something the market want (it's a journey).
* Charging per user is only one of the many many options. It does not have to be that way. Many very successful software businesses don't charge that way.
* Enterprise software is (comparatively) the easiest to self-fund. Most companies in this area are bootstrapped. It takes a single client to achieve ramen profitability for a team of 2 or 3.