As far as the forces go, the first and biggest force should probably be the legal one, companies generally can't lie or mislead while advertising or entering contracts. If a VPN company advertises that they don't keep logs and it's discovered that they keep logs it's a pretty good case for a claim against the company to get out of the contract at the very least. This all depends on specific countries, VPN companies involved, what claims those companies are making, etc. It should be noted that an employee doesn't need to leak anything for this to be the case, if the VPN company is involved in a public court case then it can be inferred whether they actually keep logs, this has been the case with at least one company.

The second force tends to work in favour of the VPN company and is the market forces involved, generally you might only have a handful of ISPs to choose from if you even have a choice as you could be stuck with a single cable company for instance. This isn't the case for VPN companies as you have literally thousands to choose from and they can be located anywhere in the world, and while this might not be a big deal if you're from a first world country with good network infrastructure and regulatory environment already it'll be a bigger deal for people living outside of these countries.

The third is somewhat related to the second, there's obviously a use case for privacy focused VPN companies whose value added product is simply to provide a good service and there's more than enough people that will want to make a business out of it. This is obviously the case for ISPs too where their value added product may be technically competent staff and ensuring that they'll uphold your privacy and won't engage in censorship, etc, but again access to these ISPs may be limited.

Also, you're still trusting Amazon to play by the rules, which is unlikely if state actors are involved as the comment (which spawned this discussion) insinuated

I had to tunnel dns through openvpn to make dnssec reliable.

On a wifi router, there's loads of leakage; mdns, ntp, things devices do to check for captive portal, weather apps, etc etc.

You can mitm https, but breaks hsts sites, unless you hack your browser