Did you ever think that maybe all VPN services are actually secretly owned/funded by governments and that they are only giving you a false illusion of privacy?
What exactly do you mean by "scammers and thieves"? The only protection you get from a VPN is privacy from your ISP. That ISP obviously operates in your country (there has to be some physical connection) and is regulated by your government. It's easy for the government to demand data from the ISP about you (or about certain usage patterns and which users have them) without you knowing, not to mention how easy it is for the ISP itself to monetize your usage data.
A scammer or thief can't as easily grab hold of that data. If you're imagining a hacker gaining access to the ISP's database or network, that's certainly plausible but it's just as possible with a VPN provider. I personally don't think the big commercial VPNs are much more secure than ISPs. Maybe a little.
Its mostly protection when using public WiFi against spoofed website. Actually, not just public WiFi, it's protection when using any WiFi from routers whose owner never changed the default password or using really weak ones.
Did you even read the OP? A VPN that has real customers but is set up by a scammer can be doing anything on your computer. You install their client. It could be a key logger for all you know.
And not all services use end to end encryption so yes there is still the potential to listen to http traffic and extract data from it, especially as the VPN client.