One big problem there is that protocols aren't sitting still in time. As more things change, like moving SMTP to ESMTP, Rebol needed to keep up, but didn't always. R2 was closed source, which didn't help. The protocol schemes were all written in Rebol, so you could hack them, which many of us have done over time, but that was an area where docs were lacking and sorely needed, so not many people could do it effectively.