It's open source, innovation is not necessarily tied to money. It may or may not be tied to it or helpful in some way. It does open a whole bunch of questions up though, like who gets the money, what if an individual contributes more work than the paid employee and the salary? I've seen situations where people are upset about where grant money is allocated and who it's allocated to, so I imagine having a person paid a salary is susceptible to similar possible community problems.

That's not to say money necessarily causes a problem, just that it can, and introducing a monetary incentive into a system that was working well with non-monetary incentives (traditional open source) might complicate things.

Another way to look at it is that open source is primarily a social system and context, and mixing a financial system with a social one often leads to problems as different aspects of our lives cause friction we're generally ill-equiped to deal with. Just look at any of the reports of people that have won large amounts in the lottery and had a negative outcome in their social lives.