Time based account suspensions already exist. IP bans are a last resort - they’re easy to defeat and don’t guarantee a particular user is blocked from accessing a site. Many ISPs don’t hand out static addresses, which means you would need to block entire network ranges to prevent individuals from accessing a site. Most of us also have some form of cellular connection.
The truly determined can just open up Opera or Firefox and use the “privacy” VPN features which are built in. IP whack-a-mole really isn’t the way to handle this kind of stuff.