I think I would have gone pretty much the same route. I have a handful of rolled posters from the 80s that dont mean all that much to me, but as i think ive mentioned, these were work rescues that would have ended up in the trash, so in that regard, no money outlay.
But when I started getting more into collecting in about 2003 or 04, I was looking for more specific things (Chaney Sr, some horror) and quickly learned how $$ so much of that material can be. So I began to branch out, into foreign posters, but pretty much have stayed in the earlier decades, looking for drawn or stone litho art. But i have bought more modern stuff too, if it has caught my eye.
Like some above have said, it's all about balance and just going with the flow. Ive never looked at it as a race, since the finish line always seems far off in the distance. I guess Im kind of like the tortoise in the well known children's story. The hare can race on. For me, it's the slow boat, easy does it, look, see, learn.
It's what makes it all so fun. And finding the next hidden gem that I alone might find appealing.