If you've been around as long as I have, and paid attention, you will see that people go through distinct "phases" in their AH career. Those may change somewhat for the individual, and the timing may be different. But looking at someone from the outside its fairly easy to see.
As you mature, learn ACM, grow in skill, how you play the game changes.
The faster you learn and adapt the faster those changes happen.
I've seen truly gifted top sticks go from newb to burned out vet in under 2 years.
Squad involvement, active involvement in AvA, or FSO, or Scenarios can add luster back to what has otherwise faded and lost its attraction.
If you have truly lost the "itch" then its time for a break. When you come back, I'd suggest trying all the new things you can think of. Or setting yourself goals, like how many kills you can get in 1 tour in a Spit 1, etc.
Some people seem to get locked into one part of AH and never really get good at some of the other parts.
Be it furballs, or base attack, or GVing, or whatever. So take a break, stay away until the "itch" comes back.
And when you do come back, make sure you've tried it all.