This delay is almost certainly due to issues arising from using the M2 chip. Apple has (reportedly) chosen to use the M2 as opposed to a purpose-designed chip and power efficiency is very likely to be horrendous. All current standalone headsets (e.g. Pico 4, Quest 2, Quest Pro, Pimax Crystal, et.al.) use ARM's custom-designed first generation XR2 chips (or the XR2+ variant).

Apple is reportedly using the M2 which is not designed to be anywhere near that power efficient. Apple can't just "add a bigger battery" to fuel the M2--adding weight makes the headset heavier and uncomfortable.

The engineering challenges stem mainly from battery technology along with the immaturity of software. I have little doubt that Apple will do well on the software front, but their decision to use the M2 betrays quite a bit of hubris IMHO. I'd expect a short 30-60 minutes of use (max) before needing to be recharged.

Folks need to understand why Apple & Meta are working in this area--they see AR/VR/XR as the next computing platform. Meta is the industry leader for a reason--they've invested billions in R&D, employ most of the talent, and have been pushing the industry forward. And even then, the best consumer AR kit they could produce is Quest Pro with a BOM of ~$900 and a retail price of $1500. Apple's device will almost certainly retail ~$2000-$3000 and the fact that they still can't make it work satisfactorily shows how far behind they've fallen.