I too was in the industry until recently and I will agree C/++/# and Java are the leading programming languages out there (although IMO C# is by far the sexiest) as I have previously stated.
I was an AS/400 RPG developer which in extremely similar to COBAL and widely used in South Africa. TCM (the people who supply/support/etc the IBM iSeries) say that there are over 2000 iSeries/AS/400's in Johannesburg. Although most are used in financial institutions/services. FNB for example runs on COBAL.
Why? IMO it's because:
1. The code works - it's been wip for 20 years

2. The hardware (iSeries for example) can handle the required (huge) transactional load.
3. Porting to say .NET is just expensive and people with skills in legacy languages and the new stuff I assume are hard to find. Cheaper to maintain.
Having said that, personally I wouldn't recommend going into this field. The money is good (at the moment), but if you are in your 20's (as I am) I was worried about turning 50 and being an expert in something that doesn't exist anymore.
I did some searches on UK job websites for AS/400 RPG developers and > 80% were for "AS/400 RPG developer required to port existing system into .NET".