I think the diet that will work best for a person is based on their taste, life experience, goals and a lot of other things. With that in mind people will do keto, atkins etc and find that it totally works for them and become evangelists for it - but that doesn't mean it works for most people. Changing your diet for permanent weight change is like changing any other habit that you're in, with the added complication of the fact that your body is wired to give you a chemical reward for doing the thing you're already doing even if it's demonstrably unhealthy and to punish you even if you're making a change for the better - you may be able to hijack that process for a few months or a year and see results, but if you haven't addressed the underlying problem then as soon as you let your guard down you're going to start rubber banding back to where you were.

That said, I also think that the primary "underlying problem" for like 90% of overweight people in western countries is capitalism-driven food culture. They want to pump us full of as much addictive food as possible, and some people are going to be more or less susceptible to that based on their genetics, but it can only get worse with time.