The point of having lower power caps on the newer servers is to ensure that if a new player joins the game that they actually have a chance of enjoying the game, including the PvP aspects, without being so far behind other players on the server and with no hope of ever catching up.
To use an example similar to one you have used, having the same power caps on all servers would mean that a new player would have an experience similar to joining kindergarten and being in the same glass as university graduates.
New content is released to all servers at more or less the same rate, it’s just the case that the older servers have a head start. If you join server 22 today you may not be able to upgrade to orange but obviously you won’t be able to immediately anyway. By the time you have a team that is ready to be promoted to orange, the power cap will probably have moved on and you will be able to.
There is nothing to stop someone from starting a game on any available server, and when they do the current level cap is clearly displayed.
I can understand the frustration of knowing that other players have access to characters and skills that you don’t but the system is there to provide the most enjoyable experience for as many players as possible and I have to say I completely disagree when you say it’s unfair.