These things have a life of their own, meaning that if you don't inoculate, some spores will blow in eventually, and if you over-inoculate, the weaker ones will die out. Inoculation is really a sign of impatience, that you want to get the stuff to break down quicker and get the soil life humming. I got 7 dump truck loads of wood chips last month, and have been sporadically throwing blender slurry on the piles of any mushrooms that I come across. A couple wet rainy days after one inoculation, that pile looked like it had a snowed on it, the hyphae was so thick. And two days later, it had all disappeared into the pile.
When you have big piles of rotting wood, all is right with the world.