I actually think this is a 4e misnomer, that results in looking at the game on paper rather than play.or even just make 0 assumptions about the number of encounters per day and make the game entirely encounter based.
...though if 4e is any indication, that'd make people very mad.
On paper, the fighter and the wizard have the same "stuff" in 4e, same encounters, same dailies.
In my play experience though, the fighter's enounter powers are stronger, and nothing is better than a wizard's daily. When a wizard used a daily, the combat held its breath.
So the wizard in my game had plenty of incentive to long rest, and definately felt weaker when they were out of dailies, versus the fighters that still had a lot of encounter juice going on.