I think a Raspberry Pi version would be awesome. Hardware-wise, the Pi 4 is probably powerful enough to run BIAB or RB - the CPU benchmarks roughly equal to an early Core 2 Duo (circa 2006), and you can get a Pi 4 with 8gb of ram (BIAB and RB use far less than 1gb on Windows and Mac, usually under 500mb of ram, so you could probably get away with a 2gb Pi), and since the Pi 4 has USB3 you could run the RT's from either an external or a 256gb Micro SD (although the USB3 speed on the Pi 4 is faster than the SD card interface). Pi 3 I don't think would be quite powerful enough, but maybe.

One issue that comes to mind would be in troubleshooting the Pi itself - we would need tech support people well versed in unix/linux to be able to do that, which with our current pool of tech support people that basically includes only me, having been a linux/mac/windows sysadmin in the past.

The main issue is computer/OS market share. I don't have up to date numbers, but to start:

In 2019, worldwide PC shipments surpassed 261 million units.
In 2019, Apple shipped an estimated 18.4 million Macs.
In the first year of sales (2019-2020), the Pi 4 sold 3 million boards.

Of the above statistics, the Pi 4 has slightly over 1% of the market share. I honestly doubt a Pi version would ever sell well enough to cover our development costs on porting from Windows/x86 to Linux/ARM - although now that MacOS runs on ARM that may very well help. I'm not a programmer though, so that last part is merely speculation, especially since BIAB for Mac runs on X86 or Rosetta only for now.

I work here