When sales of a new Apple product are started, it is normal for it to suffer from a shortage of stock, this always happens and it is also a strategy to raise the "hype" of users who want to buy the product and see that it is out of stock The media talk about them and it is true that it tends to be common in all companies, not just Apple. What happens after these first months is that the stock is normalized and shipments stop suffering these delays to stabilize and then the opposite occurs, when a reasonable time passes the company stops mass-manufacturing the product to incorporate into the lines production a new model, in the case of Apple This new iPad Pro model could be causing the stock shortage on the current model.
Undoubtedly all these are rumors that we find on the net, but it is true that iPad's are usually renewed during the month of March, so it is not surprising that this lack of stock of the largest model is scarce. In March it could come the second generation of these huge iPad Pro and even a possible renewed 12 ″ MacBook, but all this is now speculation and there is nothing confirmed by Apple itself.
Apple explained in its financial results conference that iPads had a slightly higher demand than they initially imagined and that is why they have had several problems with the supply of this equipment, which does not mean that production increased on dates key like Christmas and now it will come down again to make room for the new generations. We will have to follow the evolution of the stock and the rumors since there are not too many in the network about the renewal or keynote for the month of March, Apple may wait for the arrival of the MWC in Barcelona so that the media will "lose track" a little more towards them.