I'm not quite sure what you're arguing against here. I'm not arguing that they're good, anymore than I'm arguing that the current system is good. I'm just pointing out that even the designers recognise that the current system is so modular and vestigal as to be easily chopped out.@Don Durito yea the dmg has "3 different proficiency alternatives to the current skill system", but all of them are pretty poorly thought out & suffer from the sort of overly inclusive with one a less developed version of what exists in fate freeport without the fat fractal & even the fate community tended to find it better to use a more considered set of skills to choose from
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The other two are background & personality trait efficiencies, both of which are aspects that would be called things like high concept aspect or flaw/trouble in fate but lack the compel type functionalities & miss the mark of what aspects are by applying them so broadly as skills. There's also the fact tat so ,many spells & abilities destroy that sort of thing
Fate core has 18 skills & the ability to add more specialized ones along with all the variants that have their own skill arrays. These systems suggest even less than 5e itself & more like Fate acelerated's six... but FAE is more useful for plot/stpryboarding than playing a game because it's too simplified
The part that's load bearing is that it's necessary to have some way of adding proficiency to checks. You can do that with ability score proficiency or you could do that with the 4 skills from Microlight D20, or you can use 13th age backgrounds (pick 3 rather than the one in the DMG and the system works much better - also make them more specific). You could also bring back the entire skill list from 3.0. It doesn't matter how the PCs get proficiency to rolls, only that they have some way to get it.
The table on page 237 that lays out what each Ability is used for highlights this. The game is interested in whether you use Charisma for X, or Dexterity for Y. It has very little interest in what skill is appropriate to be laid on top of it.
At some point I suspect it was considered making skills entirely optional (Or well more optional than the options in the DMG make them).