Yaarel
🇮🇱 🇺🇦 He-Mage
The problem happens when the adventure story diverges away from seven combat encounters per day and two short rests per day. Then the class balance becomes less fine.Your conclusion is kind of in error.
Classes are balanced around 6 or so encounters and 2 or so short rests per long rest.
As long as that median is met (not every AD needs to feature this median, some days are longer, and some shorter, some with more short rests and some with none) overall, balance is just fine.
The problem is, the narrative requirement to balance the classes mechanically − seven combats per day − is narratively abnormal and unsuitable for most adventure stories.
Meanwhile, it is nearly impossible to have TWO 1-hour short rests if in the midst of a violent battle zone where seven full-on combats are actually happening. To require both seven combats and two rests is a "catch-22".
In sum.
The current 5e guidelines to link refresh to both sleep and lunch are strictly mechanically gamist − and make most adventure narratives unable to happen.
To connect refreshes to sleep and lunches turns out to be bad for the narrative and bad for balancing the mechanics of different classes.
There are good reasons why most 5e DMs reject the official rules and the official guidelines. DMs try to fix the rest problem as best they can.