Patience is the key here. I have an alt that was cryo'ed for 14 months. When I started playing it again for fun it was interesting to climb through all these inactive players. I didn't spend too much time in the arena since those inactive didn't drop me. I just focused on other game modes and on building my roster in general. That alt has been back inside top-20 in squad arena and also on top rank in fleet arena. So... It is possible to recover. Just have patience. Don't worry too much about arena for the next few months. Enjoy the other game modes until you have a viable arena team again.