All mine run on Server 2008. When the database server runs on Server 2003 and does nothing but run SQL it's real easy to move it from 2003 to 2008 (or newer, if you have licenses).
It's a hell of a lot harder to move from SQL 2005 to SQL 2012. Experience says about 25% of your applications will just flat out stop working. And SQL 2014 is such a dramatic change from SQL 2005 that you can bet most of your applications are going to give up the ghost, unless the devs have been all over it.
Now, in the real world a lot of use use applications where the devs are emphatically not "all over it". Hell, I still have to babysit an application that uses frakking btrieve. That's like bashing two rocks together to make fire. Underwater. While being boiled alive.
Now, SQL 2005 --> SQL 2008 R2 should work for almost everyone and every application, assuming you have licenses.
If you need to go back to your developer and ask them to port the DB, don't get them to port it to Microsoft's latest and greatest. Just get them to port to Postgres. Later this year GPU acceleration for Postgres comes out. From experience, it's pretty fantastic. What's more the licensing costs are a lot more bearable.
If you don't think that licensing can be a bit of a pig, go take a look at the cost of two SQL 2014 enterprise 4 core licenses. (To allow for replication between two 4 core servers.) Tell me your average SMB will afford that.
Hell, for that kind of money, you can probably get your dev to port to Postgres and never worry about the licensing issues again.
Is that proper advice for the enterprise? No. But enterprises are probably not facing the same SQL 2005 issues as SMBs, and it's SMBs that are most likely still clinging to their old databases.
"Move away from SQL 2005" is not a simple, straightforward item with clear cut, universally applicable solutions, or even reasons why companies are facing the problem. It's a tangled mess of a thing and in a lot of ways it far - far - more difficult and problematic in today's datacenters than a "simple" operating system upgrade.