Balance Team Favouritism

Why is it that the usual suspects like Lee and Fiora et al get buffed for worlds while champions that are consistently subpar get no attention at all

the same champions end up being picked most of the time in worlds, and the normal majority of players have to suffer against champions that were already strong being stronger

I just do not get it. The same champions are nerfed and buffed in an endless cycle because they somehow just HAVE to be "in favour", just not too in favour, just moreof what I assume whoever writes the patchnotes would call a "healthy dose".