Sure, just like someone who buys the game a month after release and starts playing is at the same disadvantage. But like I said, that disadvantage goes away pretty quickly as you progress, unlike past P2W schemes where you were perpetually at a disadvantage if you didn't spend money. Also, keep in mind that in terms of early access you're only gaining an advantage once you can play against people coming in later. During the early access periods it will be an even playing field, and then any sort of advantage you might gain will be quickly mitigated by the staggered release schedule as players gradually trickle in and ramp up quickly.
Bottom line, if a head start and a day or two of punishing newer players with better weapons is important to you, buy one of the deluxe editions or EA all access.