I'm not a civil engineer so I don't know for sure, but I'd guess you can't just throw a cathedral up just anywhere you want. The land has to be the right composition, you need to have good enough transport links to get the raw materials to where you're building it, you need local talent to actually build it, it can't be in the sea.

It'd be surprising if these buildings were exactly aligned. Presumably people could easily say that the respective diocese(s) are aligned though.