The schools around here seem to put a lot of importance on lineage. A couple years ago my instructor moved away and the schools I called at that time were pretty sure I'd have to relearn my form.
Yeah, you'd have to learn their forms, but since WC has comparatively short forms and there's probably only minor differences (honestly speaking) you might actually enjoy learning new variations. It really depends on the instructor. My old association basically held that their version was right and everybody else was wrong, so you started over at the beginning. But get real. If you get a guy that's already pretty good, are you going to knock him back to step 1, or work out a program that helps him efficiently transition to your lineage?
Yeah, I know a former kung fu brother of mine who insists that everybody starts over from scratch. I disagree. Sure, I make everybody learn our drills and curriculum, but I will also absolutely respect their experience and build on it. In fact, I'd probably take them aside from time to time and pick their brains to see what I could learn about their lineage. I'm funny that way.
Now if you can't stay with your current instructor, and can't find another WC instructor who will help you along, then try something else that interests you. Personally, I've really enjoyed my time in Escrima. Not your cup of tea? How about BJJ? I regret not training in grappling when I was younger. Also, HEMA looks fun to me. The world today has so much cool stuff! Good luck and keep us posted.