Quote: "Are we going to leave systems written in COBOL running for the next couple of decades? I seriously doubt it"
Why not? Imagine 100's of thousands of programmers coding flat out for 50 years ... that's what you have to replace with <insert 'modern' language here>, simply to replace what is already there. Yeah, I can really see a for-profit company doing that
Ok, I agree that support costs will rise over time, but there's no way that those will ever reach the cost of recoding everything. In fact, in the timescales you talk about, I can see that there will still be COBOL coders around, quietly taking the abuse that other programmers dish out, while taking home twice the salary

The demand will be there with the money will pay for it, the supply will follow.
As for the readability of COBOL, take a look at some of the code sometime - I called it a read-only language for the very good reason that it can be immensely readable. Plain old procedural code, with everything clearly spelt out using plain English. (Emphasis on 'can be' - you can write crap code in any language).