Not everyone involved in a religion is a believer. A lot of people get involved for their own purposes. But yes, the desire of believers to be accurate is why

Not everyone involved in a religion is a believer. A lot of people get involved for their own purposes. But yes, the desire of believers to be accurate is why I'd expect something like Q to be written down eventually. Also, people misattributing quotes to people is not a recent phenomenon. Many commonly misattributed quotes have a long history going back 100s of years or more. It's only the massive amount of information we have about recent historical figures that allows us to definitively say that the misattributed quotes are wrong. If you go back more than a few hundred years, it gets very difficult.