@sborgnanera:
you have a lot of interesting theories but from experience, players just need to tailor their iph upgrades to their own playstyles.
if you play often, opt for the low-output, high collection attempts buildings along with some high output buildings
if you play once or twice a day, opt for high output, regular collection buildings (6/12/24/48 hr)
I got to 12k IPH and never bothered with IPH after that, only upgrading low upgrade cost buildings so as to get an army of dragons while raiding, PVE supplements income decently.
From experience, I have realized manor upgrades beyond level 3 are frankly simply not worth it. In addition, my opinion is that MC upgrades shouldn't go beyond 7, takes way too long to upgrade them. However they are really good in offsetting the damage for box events.
Good luck with your theories and such. But do implement them soon before everyone has moved on with the game.