Mostly because most of the code is owned by a single guy and he does not see the problem with that.
Note the 'ed' at the end of 'work'.
The excuse cited was always that version control was impossible with languages that compile (we were on .Net) - I'm sure there's a response to that, but I didn't know what the response was, and just decided to leave in the end (amongst hundreds of other reasons)
Version control works best on plain text documents, but you can certainly check in binary assets to version control repos. I've done it even with CVS back 12 years ago, although IIRC it was a pain - SVN was somewhat easier, git is simple (re: binary files).
Actually, the simpler response is the .NET ecosystem has their own version control stuff (Team Foundation Server at very least - http://msdn.microsoft.com/en-us/library/vstudio/ms181368.asp...).
Software devs not using version control should set off as many alarm bells as an accountant that tries to keep everything in their head, or doesn't keep receipts. Obviously it set off those alarms for you - it's just sad that the developers themselves didn't see it.
Phrased another way, if compiled languages were indeed incompatible with source control then that would be a reason for discounting doing serious development in compiled languages altogether.
You can also point out that git was designed specifically for use in a compiled project (the linux kernel).
You're right. It did set off alarm bells at the time, but i kept having doubts since i myself am essentially a non-developer and was unsure if perhaps my argument was weak.
Now, especially after having read your response not only am I very relieved, but am realising that I had more admiration for these developers than they deserved.