Some VPNs don't and they get treated the same as Tor i.e. CAPTCHAd a lot, throttled, outright blocked (I've seen it happen).
Others do keep logs and use them. Guess what? They're not pointless. Lots of people don't require absolute anonymity against everyone - they just want to get over a particular firewall or shield their IP address from one particular network. But they don't include the VPN provider (or host country) in their threat model.
Can you point out how VPNs fight abuse?