I would say the vast majority (greater than 99.99%) of raises come from the threat of quitting. That can either be an active threat (where you approach management for a raise to set expectations) or a passive threat, where management wants to make sure you aren't looking around for better opportunities, and those opportunities will often pay more than they have to raise your salary to keep you, which makes retaining you after you've shopped around much more expensive.

Large companies that realize losing institutional knowledge is costly put in programs to make sure there are good expectations on what is required to achieve the next position and what the pay-scale range is for the next position (which also helps fight racism/sexism). You see this at Google (and I'm sure many other large companies), who had identified this as a problem that needed to be solved.