Whether it's a trend or not, I'm not sure.Compact Discs are much more viable (at least some computers still have the ability to play them as well as any bluray/dvd player, whereas nearly no one owns a cassette deck anymore), and through services like Kunaki cds can be made for under $2 each. I'm basically a 'local internet band' and use Kunaki for cds and when they sellout I can always make more, or not.
The whole nostalgia thing will fade fast (it's already flatlined/stagnated), once people realize what shite the format is/was in the first place and run back to their superior streaming service mediocrity.
Maybe there is an untapped market for locally released CDs but the majority of bands I've seen in the last few years are choosing to sell cassette or vinyl copies of their music from the merch stand at their gigs.