Plenty of folks have played an enormous amount of D&D and rarely been in the dungeon. They were still playing D&D.
That being said, I don't agree that it doesn't do dungeoncrawls well. Does it do them differently than 1e? Yes. Encounter focused design does change the way you need to frame your play to a degree. Can you still have strategic play? Yes. Can you still have extra-encounter exploration play? Yes. Can you still have ridiculously deadly play? Yes.
My level 13 players were in a long-abandoned, haunted, dwarven sanitarium/madhouse (a dungeon) in the Underdark. It was filled with tortured, angry spirits and spooks. A Derro clan had taken up residence here centuries ago and used it as a base of operations to raid a neighboring deep gnome settlement. The PCs were looking for the skeletal remains of a mad dwarf who died here long ago. He was born with Hydrocephalus (a rare condition that made his head grotesquely large and made him mentally disabled) so they had means to verify the skeletal remains. He swallowed a key (that allegedly remained in his guts/plumbing), which they desperately needed, when he was a little boy.
The lost/tortured spirits perceived the Derro as their Dwarven caretakers so they were not hostile toward them. But oh were they hostile toward the PCs. This allowed for a nice diversity of enemies to challenge the PCs.
The sanitarium itself had several large wings, all filled with natural hazards due to the degradation of the edifice wrought by age. It was also filled with a motley assortment of terrible and devious traps laid by its Derro occupants. I wanted this to be truly deadly so I made the level of the dungeon a lvl + 4 (I typically make it a lvl + 2 or 3). There was plenty of 1e, operational exploration of long, dark corridors; light-blazing tokens in hand, jumping at sounds beyond their sight, looking for hidden chambers or fissures to circumvent potential dangers, rogue spoiling tripwires and navigating pressure plates (or not), attracting undue attention and dashing escapes, and ultimately barricading themselves into rooms when they needed a rest and things got too hairy. Plenty of this was extra-encounter play. I had a debilitating Disease/Condition Track that the PCs suffered from due to the constant exposure to the spooks and haunts supernatural wailing and moaning and the general haunted ambiance of the sanitarium. And I also made plenty of use of Skill Challenges for specific things (dashing escapes, easing the ire of the restless dead and ultimately putting them at rest, setting traps of their own, and an extended SC to locate the burial chamber and the body by way of etched tablets used as charts, ancient runes, and after they verified the body and found that the key wasn't there, they located his overseer's chart/diary and found the location of the key).
One moment was extremely fun. The PCs were way over their heads. In the common area, they had been waylaid by a Roper, fought off (and put to rest - mini Skill Challenges within the combat) several haunted spirits, and 2 waves of Derro that were alerted by the noise. The Derro kept coming. This was clearly TPK territory. The PCs fight their way out of the room to a choke point, the Druid summons a Large Croc to hold the chokepoint for a few rounds, the Bladesinger uses Arcane Gate to port them 100 ft down the passage, and off they go: Dashing Escape Skill Challenge! They gained very narrow success in the Skill Challenge. The last check of the Skill Challenge was them securing a room at the top of stairwell (with that door being the only visible entrance/egress. There was a large pile of rubble in the room with sufficiently sized rocks/boulders to stopper the doorway at the bottom. They set a tripwire half-way up the long stairwell and had it mechanized such that it released the rocks/boulders down the stairwell and having them smash against the doorway at the bottom, sealing the chamber and the stairwell. Insert Rolling Rocks Trap!
Rolling Rocks
Init + 2 Speed 6
Trigger: An enemy triggers the trip-wire. When the trap is triggered, the rolling boulders attack with surprise. Roll initiative. On its initiative count, the boulder moves down the stairwell (18 steps/squares). The rocks are blocking terrain and cannot be moved through.
Target: Any enemy in its space on its initiative.
Attack: Level + 3 to hit Ref (+ 16 vs Ref)
Damage: Low Damage Expression for Limited Use and knocked back + slowed (3d10 + 6 pushed 2 squares and slowed).
The PCs performed another small Skill Challenge to reinforce the barricaded door, upping the DC 28 (Hard) Athletics by + 5 to DC 33. The derro (those that weren't dead due to the trap) were not going to be able to get to the PCs any time soon. Extended Rest!
We even had a PC death to a particularly horrible Lvl + 5 Elite hazard (a nest of horribly poisonous caterpillars...they destroyed the nest but not before it claimed a PC who was already ailing and out of healing surges) and two near TPKs!
So while not 1e, it was plenty dungeon crawl. That's just one example. I've never been a huge, huge dungeon crawl guy, but I've had 3 larger ones and multiple smaller ones in the last 4 years that went off just fine. I'm even able to have them at high level.
