The difference is between staying on stable and cherry-picking the latest for what you really do need, and being on everything latest.

The latter has a huge maintenance burden, the former is the, as I said already, sweet spot. (And let's not talk about combining stable/testing, any machine I tried that on got into an non-upgradeable mess quickly)

I am not saying it is easy, which is exactly why I think it should be a commercial service that you pay for for it to actually survive.