Paul Farquhar
Legend
I think people are largely unaware of how many encounters they have, and how many rounds of combat. And it clearly is going to vary depending on what kind of adventure (dungeon, wilderness, urban, political, horror, etc) is being played. Which in turn depends on what sort of adventures the group likes, etc.It is possible that with all of the testing WOTC did in the early days of 5e, they just did not know people played 1-2 encounters per day instead of 6-8.
But the idea that you can "balance" a game around any particular number of encounters per day was always wrong-headed. The difficulty of an encounter depends on the tactical skill of the players (and the DM) far more than it does stat blocks. If that wasn't the case you might as well be playing Snakes and Ladders, where only the dice rolls determine the outcome.