At first, that new term is not just the "updated term" that everyone knows is now considered less offensive.

At first it's partly activist, and when you adopt it it means that many people won't understand you, think you're criticizing their use of the previous term, or think you're probably activist on other topics too, when you think you're using a normal, neutral expression.

So most people are sceptical and wait with adopting new terms until they're widespread.