the blue dial...just look at the 40th anniversary and the 5740 and the discontinued 5980.
If the 5726 and 5990 comes in blue, their fate will be different.
That’s just my observation, no data to support, just like what you observed.... the 5726 has a more complicated AC but not much love... oh dear...if I got ban for answering you, I’ll blame you 😳