Gotta love "progress" as the ultimate goal. Ignore how you got here, whether you made a wrong turn, or even if you're happy as-is and don't need to change. Just keep pushing forward and moving around the deck chairs!

You're assuming that the ending is already written and the long term value of LLMs is already known.

Someone not using them could get left behind if LLMs turn out that to have a consistent multiplier effect on productivity. That person also may not actually care about being "left behind".

Someone not using them could also save a bunch of time and effort if LLMs don't pan out and don't add a meaningful value over the long run. That's not to say they don't add any value, LLMs could be relegated to the role of a much better predictive text engine that gets used regularly but isn't itself a large enough gain to leave anyone behind for not using predictive text.