People all over the world were using the main chain for all kinds of transactions and the mempools were moving along. The spam attack caused the fees to rise to ridiculous levels for months. People who use Bitcoin as money have lives to live, they can't wait for the Ordinals crowd to stop scamming each other. They were forced to find alternative ways to move value. Once the spammers ran out of money and the fees went down, people had already found other ways and never looked back.

It's not easy to see, but check the stats. The mempool's activity never recovered after the spam attack.

And as a bonus, check the tweets from the time, spammers announced the attack. And then, they were gloating and making fun of normal people who couldn't afford the ridiculous fees.