IF
DCL were to make this change (which right now it doesn't appear to be imminent, though I am keeping my fingers crossed) I would suspect they would follow suit with many of the other cruise lines and allow more flexibility with the type of test as well. For example, Carnival accepts Rapid Antigen as well as NAAT (e.g. lab PCR, rapid PCR, IDNOW, etc). I've been doing lots of testing as we head towards our cruise later this month (wanna know if I get it so I can still get that 90-day exemption!) and the rapid antigens and rapid NAAT (IDNOW) tests have been SUPER easy to get at basically any walgreens I can find. Free as well, and results are back to you within the hour. I did do a lab PCR test and even got those results back in less than 48 hrs (they say 48-72).
As you said with case numbers way way down, testing is not only VERY available but also seems to be running pretty smoothly and efficiently.
Oh and also Carnival has added that if you're "up to date" on your vaccines (which means you've received all the vaccines you're eligible for, including a booster) then you can test as far as 3 days out. Others have to do 2 days.