but sensible head says 2×11 for greater gear range and versatility.
Versatility? Yes, probably
Gear range? ONLY just, and that’s if you’re running an 11-32 and a compact… 428% plays 420%
The only bind with 1x for me is on the road, where there’s several ratio gaps of more than 15% on the 10-42 cassette (none are more than 20% though), where a 2x setup typically has slightly closer gaps. Remember that a 2x setup is only effectively giving you maybe 13 or 14 distinct ratios, and that the other 8 or 9 are all duplicates. But given that those 13 or 14 are covering roughly the same range as 11 on a 1x setup, that’s why they’re slightly closer together.
I’d say the more offroad you ride, the more 1x makes a case for itself. If you do a lot of road, and like to keep pedalling at a constant cadence, then 1x might be a little frustrating. Mind you, so would a compact with an 11-32 casette!