Exactly. After a threshold, the quality and size of the lens the dominant factor in picture quality.
My 14MP Nikon digital takes better pictures than my (surprisingly good) 8MP Android, but it has a Nikor glass lens that’s probably 10 times the diameter and thickness of the one in the phone. To take a photo worthy of 41MP, imagine the lens you’re going to need, and the percentage increase in size and/or cost (some tradeoff between the two, but at levels of both I can’t see how they could make work in a cell phone).
41MP may be twice the bandwidth of professional cameras or whatever, but I bet the lens alone on those cameras costs about 20 cell phones worth.