Why are we even talking about the degenerate strategy? Does anyone actually do that? The problem isn't that some autist rests after every fight, but rather that there's little reason to play well and conserve resources - the difference in terms of time saved between optimal and average play is small enough that it doesn't matter in practice. Hence making the resource management irrelevant, and caring about it like Prime Junta nothing but self-imposed difficulty.
I don't mean this as a slight, for the record, I do play both IE games and PoE this way as well, but the altered rest system in PoE doesn't factor into this preference.
Excellently put. I've tried to say the same thing so many times. At some point in playing through PoE, you feel like you are better off switching to Story Time because tactics are the same, your equipment doesn't seem to matter. At least in Story Mode you would get through the grind faster.
We should note though, that the issue with resource management being irrelevant was already present in BG/IWD. You would finish both games with far more scrolls and potions than you would ever need. This partly has to do with players being inclined to load game if a character dies during combat, or if they use more than a couple of potions, etc.
How would you disallow backtracking? Honest question... I'm frequently wondering how would someone promote persistence
Ultimately, you can't. It's a videogame, and a player who is determined to abuse the rules, and play it as a videogame, not as an RPG, will always find a way to do that.
If you try playing this way in a PnP...
"Due to the clatter of the 25 dark elven swords you are carrying, you have now attracted the attention of a nest of gricks. Oh, my, you are almost overwhelmed by disgusting skittering sounds. Roll for initiative."
Who would have thought - what is common practice in PnP leads to "degenerate strategy" in a cRPG, namely the horrible practice of loading savegames. Lol.
Still, to provide a possible solution:
A designer could ask a developer to implement an algorithm which tracks if the player is entering-exiting the same few areas in succession, and after his behavior becomes "suspicious" enough, throws a random encounter at him. It's nothing difficult to do. Unless the designer thinks random encounters are haram, because players can load their game and retry. Big deal. Like we never did it in, say, Darklands.
Darklands solves the problem with rest-spamming outside of the city (where you can rest free of charge for inn accomodation) by steadily increasing the risk of guards or bandits finding you.
What's even more clever - after every day of resting in the woods, the player is shown the increased risk of being discovered and can see how the risk increases. Even if you try to savescum a few times when the risk is at 12, you will give up after you are unable to rest four times in a row. With time the player learns to expect to have zero chance of resting once risk is 12 or above, and is naturally dissuaded from save scumming.
A similar solution could prevent the player not just from rest spamming but from backtracking. They figured this out in 1992, can't be that big of a problem, if someone really wanted to address it.