It would be more helpful if freelance sites would make low threshold for $/hour price of each profession.
However we're far far away from this and now we has to unite and start this off by ourselves
Even if there is a Union project developers or employer can always find a web developer that will suit his need in terms of price because web developers are in competition and there are newbie web developers that still want to build their portfolio and they will accept a much lower price the union has set up.