All of this discussion comes from a bad reading of the rules, honestly. The game never advocates a high number of encounters per day. It gives you a daily budget in terms of XPs, and all it says is : "Assuming typical adventuring conditions and average luck, most adventuring parties can handle about six to eight medium or hard encounters in a day. If the adventure has more easy encounters, the adventurers can get through more. If it has more deadly encounters, they can handle fewer."
After that, the problem is that as most people play with options like feats and multiclass and quite a number (at least on the forums) powergame with this, encounters need to be extra hard to reach the level of difficulty listed in the DMG.
And obviously, it's really hard to balance things with only 1-2 encounters per day especially if the players know about this, as those who can will go nova, and outshine anyone else in every single combat, not even mentioning those recovering on long rests compared to short rests etc.
So no, there is no recommendation, just a simple statement of what COULD be handled IF you only threw medium to hard encounters are a really typical group (which no one ever does anyway). It would be nice if people who are bent on criticizing the system (yes, it's not as precise as 4e because the overall system is more fuzzy, but also way more open-ended, as D&D should always have been) would actually read the rules and stop repeating hearsay that has no ground in the rules themselves...