I say this everytime I see a NetBSD post but they still have tier 2 ports for Dreamcast, Sony NET WORK STATION, Zaurus, Sharp x68000, among many many others that I'm less familiar with.
It's why it doesn't really bother me when, say, the Linux kernel drops hardware support for older architectures.
Much respect to the NetBSD and port maintainers.
Reading raid(4) [1] it looks like RAID-6 is not supported: I would think with drives sizes being what they are in recent years (decades?), protection from a double-fault during a re-stripe would be important. Or is RAIDframe mostly supposed to be used for 'smaller situations' (like a boot drive)?
[1] https://man.netbsd.org/raid.4
I first ran across the "RAID-5 is dead" 'meme' almost twenty years ago, with concerns that when drives reached >2TB you get higher chances of failed rebuilds due to BER / UER rates:
* https://www.zdnet.com/article/why-raid-5-stops-working-in-20...
See also 2013 follow-up:
* https://www.zdnet.com/article/has-raid5-stopped-working/