Apple hasn't officially commented, but two possible reasons for the delay were posed by Gurman. One is that Apple simply wants to get in a little more design testing before consumers get the product in their hands. The second reason is that Apple is still working on the logistics of actually distributing the Vision Pro.
Gurman also noted that the headset would have a very carefully managed rollout. Certain Apple employees will be brought to Apple Park in California to train on the device, and those employees will then train others. Apple stores will have a special area for customers to test the device, sales will be by appointment only, and there won't be any third-party sales. This means you can only purchase straight from the company.
Given the wide range of accessories like headbands and lenses that will be available for the device, it makes sense the company wants to keep it in the hands of people who know it best.
It was just back in July that Apple had to dial back production forecasts because the headset's intricate design led to manufacturing delays. Less than 500,000 units are expected to be produced in 2024, and it will only launch in the US at first, with the UK, Canada, and other markets coming later in the year.
Apple is expected to launch new iPads in March, so there's a good chance we'll know more about the device then.