Robert Comsol wrote:
Has there ever been a decent explanation, both in terms of show production as well as in-universe why the Star Trek universe is flooded with Miranda-class starships in the time of TNG/DS9/Voy but seldom (if ever) populated with Constitution-refit-class ships?
The Constitution Class Enterprise
(i.e. NCC-1701-A) had the trademark of being "Kirk's ship", thus it's appearance in TNG at a time when we still had movies with the original Crew would have confused general audiences.
In-universe we might consider looking at the analogy of Nelson's Navy in the early 19th Century. The Royal Navy still had ships of the line like HMS Victory (or the fictional HMS Defiant depicted as a painting in "In a Mirror, Darkly") but the young US Navy felt that the faster and more maneuverable frigates like the USS Constitution
would be more efficient and usable, and this turned out to be a good decision.
In a Trek context the Miranda Class could have equally turned out to be design that allowed for more flexibility and use than the Constitution Class that may have started to look like a dinosaur.
Alternately, we do not know if they could already do baryon sweeps ("Starship Mine") in the 23rd Century, something the Constitution Class might have required more frequently than starships of the Miranda Class.
Baryon sweep technology may have arrived too late to "save" Constitution and Soyuz Class starships from the junkyard.
I propose the constitutions and Mirandas simply represented a high-low mix similar to f-15/f-16, f-22/f-35, and Ticonderoga/Burke. While the two classes have broadly analogous design elements and equipments, suggesting they were of the same equipment/Technology generation; Connies have the big deflector dish absent from Mirandas. All later high end federation ship designs like excelsior and successive enterprises down the line all had the dish. This suggests Connies were also the high end of the mix and were correspondingly more lavishly equipped for higher end, elite missions, while being more expensive to man and run and somewhat less flexible in performing low end yeoman missions. Miranda with two shuttle bays and no deflector dish could be designed as low end of the mix, meant to fill more pedestrian missions and produced in quantity to fill out numbers for the star fleet in case of war.
Typically in any systematic procurement plan, higher end assets in any fleet are kept more up to date, and replaced more promptly as they became obsolescent, while lower end assets, are allowed to soldier on longer.