There are in total 70 DDG-51s in service divided into 5 subclasses. Those are the Flight I (21), Flight II (7), Flight IIA (37), Flight IIA TI (12)and Flight III (0).
28 ships are assigned to the BMD role (DDG-51-78), the oldest (DDG-51) are now 31 years old, while the rest of the Flight IIA, IIA TI are not BMD capable but its software are updated to the latest Aegis baseline 9. The 28 BMD capable ships are the backbone of US homeland defense, while the rest are hard pressed for global policing duties.
The last breed of the class is the Flight III, with the first (DDg-125) are now being fitted in HII shipyard Pascagoula, a total of 15 are in various process of approval and construction. Which if we calculate that one of these ships took 2,5 years to build, looks like the US is no hurry to induct the DDG-X in the near future. The Flight III will replace the Ticonderoga's in fleet air defense role, equipped with the most advanced naval radars on the market today, the AN/SPY-6 with 37 RMAs, which is 30 times more sensitive and can simultaneously handle over 30 times the targets of the existing
AN/SPY-1D(V).
There's also concerns about the
ballooning cost of the DDG-X and the USN has prioritized the construction of submarines and next gen attack submarines (SSN-X).
In short, we will see this ships for a LOT longer. Am not betting the DDG-X to come online after 2040. All the while the US is in critical need for this asset. For Turkish navy, I don't see why you would want one as you're now developing the TF-2000s
