Because AI meant "make computers smart like people".

We taught the computer to spell check, but the computer still didn't feel smart like a person, just smart like a machine so that obviously wasn't AI. We taught it to do algebra, same thing. With LLMs though, now it really does feel like an artificial human, so this time it really is AI.

Right, but I remember when spellcheck first started to be a thing, and people were like "Wow proofreaders are out of a job, ai is so cool", but then it became normal.