If I’m understanding that diagram correctly it implies that “the right” has held its positions and “the left” has marched inexorably further to the extremes. In my view that’s demonstrably untrue. While I wouldn’t argue that some elements of “the left” have become more or extreme, when you consider the political discourse now I don’t see how anyone can argue that “the right” hasn’t done the same. When I was younger “the right” was that of Thatcher, Reagan and Major. Now it’s Farage, Tice, Lowe, Badenoch, Yaxley Lennon. The first three would have found the second group completely unhinged and distasteful. The biggest “left” party in the UK has Starmer, a fairly pragmatic centrist, as its leader. In the US it’s in disarray but its last leader was Biden. Again, hardly a bastion of extreme leftism. I can see how that diagram holds comfort for those who like to think that their own positions haven’t changed but everyone else’s has though. There’s a a lot of that self delusion about now. (Last two sentences not aimed at you but a general observation).