Between a weakly armed patrol frigate and a Arleigh Burke class destroyer, there are a lot of options, which could be cheaper than a Arleigh Burke. Most navies have such ships. The failure of the LCS program is the cause of the problem here.

A patrol frigate could replace a destroyer for patrol duties (as could an LCS, even those with the defective gearing), but the situation today is much more dangerous than 15 years ago. To use a warships against drug smugglers is anyway ridiculous. That is normally not a task for a navy (stopping drug smugglers on one route will anyway not solve any problem; the addicted in the US will buy drugs from other sources. Fentanyl is not even coming from South America). Today, Russia and especially China are a much bigger threat and ships have to be built with them in mind.

Therefore, adding at least a small VLS (for ESSM) and a sonar would better - even if at some point ocean-going unmanned vessels with ESSM and sonar will be available.

I still consider the decision to replace a class because of the delays with another one, which was also cancelled because of delays, to be very interesting politics... For both classes, the issue causing the delays (lack of skilled workers?) have to be solved.