If it happens, everything is going so freaking expensive. A level 7 mortar for example is 3.2M gold, and most of the mortars are double the price of the ones coming before it, probably making the level 8 mortar 6.4M gold. Since mortars are available for upgrade with every town hall, a TH11 mortar could cost well over 12M, which would require five storages and/or storage upgrades.
Such a large upgrade would take forever, since just about everything (including troop levels) would need upgrades as well.
On an unrelated note, my second tesla is upgrading to level 4 and my collectors are almost all level 10.
