The user behind the account has a stronger claim to the value of the account than the website

Legally, they absolutely do not. Regardless of how shitty it is, a user has no rights whatsoever to anything on these platforms. Doesn't matter if you've had an account on Twitter since day one, have a million followers, and because of that facilitated tons of ad revenue for the platform. Literally none of it belongs to you in any tangible or legal way.

These are chickens that people never believed would come home to roost. These social media companies have been around for so long and feel like such major players that people don't think about things changing, and what that change means when they've built entire communities or businesses on these platforms. This is what happens when you build a life or career on a foundation you don't control. The rug can be pulled out from under you at any time, and you have no recourse whatsoever.

You're not even a tenant to these companies. You are not the customer. You're the product they serve up.

This would be like a bank claiming all the money in your savings account because you haven’t made any deposits or withdrawals recently.

Many banks have features and services that require a minimum average daily balance and/or a certain number of transactions each month. Plenty of them have inactivity fees. And they'll tell you that you signed papers agreeing to these things. Are those agreements valid? Doesn't matter. Can you afford to sue a billion dollar banking and investment company to find out?

N.B.: I'm not endorsing these practices. Just describing the reality of them. Social media is a cancer. Capitalism is killing the planet. And all these problems lay therein.