The idea of a band "democracy" is a pipe dream. Get 4 of 5 guys together and you'll get 4 or 5 different ideas of how things should be done. A band without a leader typically goes nowhere, and wastes all their energy in disagreements. A band needs a leader, so that when differences of opinions arise, they can give final say. To be the leader you must have people who want to follow you. Perhaps you are so charismatic and awesome that you'll find a bunch of pro musicians who want to invest time in your project, for free. This is a one in a million situation. The other way is to pay them. Pro players are busy and typically uninterested in playing for free. They are busy with paying gigs and when they have time off they'd rather rest than do free work. If you have paying gigs scheduled already, this is incentive for a pro player. If your project is a start up, you have almost no incentive for a pro musician to invest their time. Paying to get pro players and to establish yourself as the leader is a pragmatic approach.