These show (for some) this is possible long term (which is important) but, what counts more (I think) is how many made it vs. how many dropped out.
If I gave you a short list, but longer than your short list (or a long list, also longer than your long list) of n=1 vegans that made it a decade or more and said “Vegan is good” - I somehow think maybe you wouldn’t agree so quickly.
You might ask about how many tried to get those numbers. I suspect that a very large percentage of people that try vegan (i.e. not raised by vegan imposing parents) drop out after not too long (due to health issues like auto-immune problems, fatigue or due to problems maintaining the lifestyle - or just so much food prep plus difficult choices to make to get all the right proteins and fats as well as maybe having to supplement).
It would be nice to know - of 100 vegans starting 10 years ago - how many still are vegan and healthier than they started. I bet it is less than 25% (maybe much less).
Carnivore seems to have fewer problems - food prep is easier, all the right proteins and fats (if grassfed) are there, auto-immune seems to get fixed vs. evolve, fatigue (don’t know?), supplementation might be less but still maybe necessary. So, to me, Carnivore long term (decade+) success for someone seems less dependent on those sorts of things and more dependent some potential health issue evolving (things like continual constipation, blood numbers for sedentary people go south, depression, discovery of cancer growth being accelerated, etc.).
Given all of that, I can see Carnivore doing better than Vegan in terms of the 10-year percentage still happy and healthy on the diet but, can’t be sure without the data (number of people that drop out and why).