OP, I think you're confusing seasonal availability with the season itself.
Consider a few things: During those seasons, as far as I know, a lot of busts take place (especially bigger suppliers). In these off seasons when supply is gone, someone WILL be there to take their place, initially with a lower quality product, then some better stuff comes around. then the cycle repeats.
Unfortunately, for some areas, the "top quality" tends to be slightly cut methylone/mdma, or just straight methylone.
BTW, I'm talking about Molly, not pills.