I think I've finally fully mourned the loss of the 'Marathon' name to the clearly inferior 'Snickers' - bring 'em back at the size Marathons bars were, that'd be a thing!
Haven't heard anyone caring about the name change since the 1990s. So I'd love to know where you're seeing it all.
It sounds more like you are whingeing about a private Corporation deciding to sell a very small amount of something to a few older folks using nostalgia. (Literally in Morrisons alone)
And the language you use suggests a desperate need to seek some mental care. While I'll agree, a large part of my generation (just old enough to remember the pre name change bars) are responsible for voting idiots who do not fund mental health care. It's been rare over the last 50 years that those parties won with anything close to 50%. So please remember we ain't all arseholes.
In the US, the Marathon branding was used for a 12” long caramel braid covered in chocolate. The marketing was that it was so big, it would take a long time and a lot of effort to finish (like running a marathon).