Why do we need so many data centers in the USA?

I know this is probably a stupid question but please entertain it for me. Why do we need so many data centers in the USA? I keep hearing about them building them left and right, latest one we hear about is the one from Kevin O'Leary using more power than the state of Utah. But what are they using it for like why do we need them? We have been powering the web for decades now, and AI like Gemini, Claude, chat GPT all that. They seem to have been doing fine. So what do they need all these data centers for? I'm like honestly confused