I completely agree.
The one thing that hasn't been tried is making healthy food cheaper and more readily available, and giving children a proper education in school about how to cook filling, nutritious and affordable meals - and snacks.
It's always the stick and never the carrot, quite literally.
By making unhealthy but tasty food more expensive, it becomes even more desirable, psychologically. When it's more expensive, it's aspirational. It needs to be unsexy and unappealing.
If you want to be more radical, stop all adverts for unhealthy foods. Slap health warnings on wrappers - it won't deter everyone, but it might deter some.
Do a full-on charm offensive with healthy foods, while also making fruit, veg, fish etc much more affordable. Teach kids how to whip up a quick snack that's healthy, and how to cook really delicious dinners that aren't crammed with fat and sugar.
If I get caught hungry while I'm out and about (I'm often missing meals!), I need to be able to grab a healthy snack/light meal that I can eat on the run. I rarely find fruit to be substantial enough to keep me going and other options are typically very limited. Make it easy to make healthier choices. Pay a good advertising firm to make some ads with ideas of healthy, delicious food/meals - think M&S style, sexy foods but healthier! Sounds daft but if shown regularly, it will start to penetrate into the collective consciousness - it's why advertising works.
But all of this will piss off the big corporations, and cost a lot of money to implement - and in reality, the government doesn't really give a shit. They just want extra £££ in their coffers and ass pats for looking as if they're trying to do something.