The mats add up once you’ve got a stable of maxed heros and then you’re to the point of only maxing a hero now and then because not every hero adds use to your roster
Once mats stock up, feeding slows down as does the flow of new “must max” heros. Which in turn allows to max a hero you do receive and have mats for the day of reception with stocked up resources
Mats and camps are designed for a steady flow and keep up with each other quite well
Purchases throw it all off. Biggest complainers about not enough mats: spenders
SG doesnt put a cap on how much players spend. They’ve implemented events and special mat offers to help out but a few purchased mats a month wont keep up with 2 dozen heros a player summoned with 1 to 2 months, just not possible.
Atlantis chest helps out a bit with this but RNG can still interfere.