They do not trace the shipping dates at Apple. For a few weeks or even I would dare to say months, Component shortages are taking off in technological products of all kinds (and beyond) so that in Apple as it is evident they do not escape from it.
The 24-inch iMac usually since their arrival have enjoyed a fairly stable stock without being good either, but in recent weeks this has been decreasing considerably until reaching the site they are today. New 24-inch iMac models are expected to ship on December 28 and no, it's not an April Fools joke ...
More than a month to ship a basic 24-inch iMac
The period of time that we have to wait right now as of November 25, 2021 if we want to buy a "basic" 24-inch iMac is more than a month. When we choose the base models we have this shipping time and The curious thing is that if we configure the equipment to our measure we can obtain the equipment a week before. It is really curious and although the waiting time is similar in both cases (one week less if we add our own configuration) the shorter wait means that the demand is much higher in the basic models of these new iMac.
Be that as it may, it is possible that The iMac presented last May do not recover the stock these weeks so in the event that you have to jump into the purchase of one of them out of necessity, do it soon and you arm yourself with patience until you get. It may be that once the order is placed, the delivery time changes for the better or not.