Yes, but people have to be ABLE to pay for your software. I simply cannot afford nginx+ for a hobby, and I'm a "free" asset when I make decisions for a company that CAN pay. Also, a startup may use the 'personal' license pre-revenue, then when it is time to scale up, they have to pay. Their features are coupled to your product, and they are going to pay because they have to (or rewrite a lot of code), a 'trial' simply isn't going to allow this to happen.