Sweeping bans of users based on shared IP addresses should never be more than a very short term stopgap solution. There are other ways to solve these problems.

Sweeping bans of users based on shared IP addresses should never be more than a very short term stopgap solution. There are other ways to solve these problems. As just one example you could support protocols like U2F or FIDO2 that take brute forcing off the table, and the brute forcers go away. As another example I offer free unix shell services to the general public. Lots of people were using Tor to create accounts for cryptocurrency mining. Instead of banning Tor I blocked all outgoing traffic to all major mining pools. The mining abuse stopped. Try to find ways to remove the incentive for bad behaviour, rather than throwing out the good with the bad.