The COBOL wiki page cites the Gartner quote, but there isn't a source from Gartner provided. It is all over the Net. 80% of businesses, 200 billion lines of code, 5 billion new lines of code each year. Some places, the numbers vary a bit. However, one number is almost always missing from that Gartner quote on the COBOL wiki page, and missing number is the year. 1997. Let's assume the quote was true, in 1997.
I have worked in COBOL for 20 years, and for the last 13 years I have witnessed COBOL development disappear.
ERP solutions? The last one I know of that had at least some COBOL in the product was PeopleSoft, when I talked to PeopleSoft reps at an IT conference in 2004. I was working for the UW at that time, and I talked to literally dozens of people, maybe upwards of 100, from universities all over the country. A very common story was repeated. "We replaced our homegrown ERP solution, written in COBOL, with " PeopleSoft, Oracle, SAP, SunGard. Delve into the careers links of those companies, and look at IT positions. See if there is any mention of COBOL, DB2, CICS, etc.
Healthcare? Well, I worked for GE Healthcare for 3 years, and they were among the last hospital clinical software vendors writing in COBOL. 3 big layoffs in 3+ years, an office that dwindled from 600 employees to under 300 employees, clients converting to Epic or Cerner. Not a very bright future for COBOL there. Neither Epic nor Cerner writes in COBOL. Check out their career pages. McKesson appears to still be written in COBOL, but I see a number of hospitals converting away from them as well.
State and federal government might end up the last bastion of COBOL, but some of those projects have gone away. Completely replaced with .NET or Java.
At 44, I'm one of the youngest COBOLers I know. Oh, there are 5 or 6 I know who are younger than me, but the 100 or more others I know are probably on average 10-15 years my senior.
IBM 390 and zSeries, HP NonStop, Unisys 2200, and Unisys MCP are the big iron boxes out there running COBOL. Every one of them supports Java development. From what I have read and know Java on big iron, which is mostly limited to the HP NonStop, if it is done right then Java can replace COBOL over time.
There have been efforts, that I know of or worked on, since 1994 to replace clunky mainframe green screens with GUI front ends written in VB, .NET or Java.
A lot of COBOLers I talk to who are certain of COBOL's future are out of work, like me, and aren't finding work. Best shot I have is a state gig where there are likely more than a couple of people within a few years of retirement. Assuming I get in, I expect over the next couple of years my role will evolve into how to clean, efficiently, and without interrupting the business administer a lethal injection, figuratively speaking, to COBOL through step by step replacement.
Finally, back to Gartner. They charge for everything they publish, and it ain't cheap. But venture over to Gartner.com, set up a free account, go to the Research tab, and search on the keyword COBOL. You won't get the whole article, but you will get a summary and a snippet. Reading and analyzing Gartner's work, I think it's very clear they are signalling the death of COBOL.