What is the incentive for quality?
You aren't looking at the average workaday C program from that era. I guarantee you that OpenSSL, for example, does not look cleaner than code of today.
The challenging part of us in the software maintenance job is to balance a need to refactor with a need to add features. It colors your opinion about a lot of things. You start to evaluate methodologies, technologies, frameworks, and even library choices by their impact on long term maintainability.
I frequently find myself at odds with a primarily greenfield developer in tool choice because I'm looking forward into the future and it doesn't look pretty.
I came to the same conclusion and for most projects there's not really a lot of good choices there outside of those two.
Even more disappointing was that RIM/Blackberry had every opportunity to take that mantle (business/enterprise IP telephony) and didn't even try.
I did my internship at Nortel. A decade later and having worked from small shops to IBM and beyond, nothing comes close to the quality of people/code that I saw at Nortel.
From another perspective:
It is up to you to carry the torch now.