Yes I am too. I wasn't very clear in my post. What I meant was that the guidelines don't account for this at all, nor provide any suggestions about how to plan for or adjust combats based upon the adventuring day.
Now common sense applies of course that combats will get harder towards the end, and it very much depends on how well the party conserves their strength. And in a sandbox its not that relevant anyway. But some thoughts and maybe some scaling advice would be nice.
Having a table that states xx number of xp = deadly seems kind of pointless with so many moving parts
Especially since their "deadly" means "not completely pushover"...
The fundamental thing they should have done was to assume "too few" encounters rather than the current 6-8, which is definitely uncommon in many campaigns and definitely "too many" generally.
By this I mean it would have been so much more useful if they assumed 3-4 encounters; made "deadly" commensurate with that, and then said "if you have many more encounters than that, be sure to halve the difficulty of each".
Because that is exactly what they do anyway! It's just that not all of us appreciate a string of 8 individually meh encounters.
Some (most?) of us want there to be some excitement, danger and challenge
in the encounter itself. Some (most?) of us want more than merely the excitement, danger and challenge that comes from having to face that eighth encounter "low on gas".
Especially since the game is set up to make it
trivial to "refuel" (long rest) well before such an individually meh encounter becomes exciting, dangerous and challenging due to "low on gas".
The entire foundation of the encounter model is broken.
With the guidelines assuming 3 encounters, the "deadly" rating would actually live up to its name, and resting "before schedule" wouldn't have become such a powerful (I'd say disruptive) strategy.
No longer do I need to make up story-based reason after story-based reason for why you need to press on and shouldn't rest, merely to satisfy an impractical and unrealistic design assumption!


Instead, coming up with time constraints would be
optional, and would be coupled with (the fairly obvious advice): "if you double the number of encounters, consider halving the difficulty of each one".
It irritates me to no end that the designers never seem to have to face this subject. Are they even aware how big of a problem this is for some of us? Have they ever adressed the way they built in ridiculous amounts of time-pressure to make their game even work?