Folks, try being a teenager 25-30 years ago, with maybe 1-3 decent tickling stories per year in Penthouse & Variations if you were lucky. We're spoiled beyond comprehension today.
That said, for me at least, after the initial binge/gorge/purge when the Net first blew up, I have to admit it DOES get a little old after awhile (tho it was quite a long initial b/g/p

). I'd imagine any fetish is similar, although tickling does appear to have a particularly short half-life.
But on the flipside, I've also discovered "specialties" I never knew I liked, and I never get tired of the stuff I do like, tho I am quite picky these days. And all the amateur/homemade stuff is supergreat when it's great, if that makes sense.
Maybe that's the problem. Tickling seems to be such a specialized fetish; unique for everyone. Has to have something to do with most if not all of us being 'introduced' to it in early childhood.
FWIW these complaints seem to surface fairly regularly, and they always seem to be from those wanting very extreme material. I'm not making any accusations or judgments, just my typical observation that authentic yet legal material of this kind is going to be difficult to produce at best, esp. w/models one is likely to find attractive.