Your attempt at debunking Watchdog's example is also flawed. Windows 98, 2000, XP are all completely seperate products. mIRC v6.03 and mIRC v6.12 are not seperate products. I think that is a pretty important distinction to understand. Also, I won't get into comparing the resources between the two software companies here
That said, I don't think he should go to the trouble to update 6.03. Software development works by moving forward, not by bending over backward to please a small minority. If you have problems with 6.12, suggest alternatives to that version and help it to improve.
These people have paid to get told they can use their old versions, which they are happy with, and get crashed every 5 secs, upgrade to a version they don't want to use, or lose their money and go to a completely different client.
Nobody has been 'told' anything. As you said yourself, you have been given a choice between 6.03 or 6.12. What you're asking for is beyond anything that Khaled has ever offered in the past.
Of course, this is all just MHO.