For what it's worth, if you customize the difficulty of your game (which you can do at any point, including after reaching the 40s), you can change most things, including resource drop rates and how much effort it takes to mine them, xp rates, Pal encounter rates, capture rates, etc.

I had a similar experience as you; by the time I hit 42 or so, I had the capture power maxed out, and most eggs were not giving me anything interesting, and I had the whole map revealed, so exploring had lost its luster and I was not enjoying the thought of grinding out another 6-8 levels to start being able to tackle some of the harder challenges in the game; I set the XP rate to x4, and doubled the resource rates, and it pretty much solved the problem for me.

Obviously if you're playing on a server this isn't an option, but if it's just your own single player game, consider trying it; you might find some settings that smooth it out for you.