I've read that there are now VPN providers that just use someone else's VPN engine. So they don't have to know wtf they are doing.

For a product that's 50% snakeoil and marketing, that approach seems reasonable? It's easier than actually doing the leg work.

Only 50%? I'd put it much closer to 100% tbh. Why people are so eager to funnel all their traffic through some of the shadiest businesses on the Internet is beyond me...