I'm definitely not on the same page with you. Players IMC have access to rituals when they seek out npcs that have them in game, or find ritual books as treasure, or find them graven on ancient stone tablets. They do not just get to spend the money and learn the ritual; they have to find the ritual first.
Obviously, everyone plays a different game, and play how you like; but I strongly feel that the finding part of acquiring a ritual is something that is in the dm's hands, not the players, and I would feel like the players were trying to usurp my authority if they just declared that they got such-and-such a ritual.
As an example, in the biggest town in the pcs' starting area, IIRC all rituals of up to 8th level that are in the Players Handbook 1 are available, along with a couple specific ones from other sources and a couple of homebrewed ones. Meanwhile, one of the wizard pcs lives in his master's tower (master has been gone on a journey/missing since before the game started), which contains a number of other rituals- but they aren't easily accessed; they are warded, trapped or hidden in shelf after shelf of books.