I'm not sure what you're asking here. If you're asking why someone who is unwilling to upgrade from Windows 2000 to XP or Vista need to upgrade to Paint.Net 3+ then they don't. It's not possible. Paint.Net 2.x runs just fine on Windows 2000 though and when Paint.Net moves to 3+ all those users (which is admittedly a TINY percentage of the overall Paint.Net user base) will have an unsupported and no longer developed piece of software.
So the question stands, since Windows 2000 will become a piece of software that is not longer developed or supported.
Well you're probably not a programmer either. In my situation I have an installed user base who uses a tool that is going to (has?) become unsupported. The user base likes the tool and are themselves programmers and the source for the tool is available. While it doesn't make sense for Rick to derail progress for such a small user base it does seem potentially worthwhile for a fork to occur so that we may continue to support the product ourselves (and perhaps pick up some outside contributions) until such a time as we meet the requirements to upgrade to a supported version.
You are right, I'm not (much) of a programmer. Since the sources for the versions of Paint.NET that work with Windows 2000 are available, though, what is the problem? Are you waiting for Rick to extend new features to you or are you and whomever you represent ready to pay to add those features?My main point is this: Windows 2000 has the features that you want and need. You do not want or need the features in Windows XP and beyond. Since Paint.NET is adding new features that will require Windows XP and beyond, you are hoping to have those features on your older operating systems. So you are hoping for new features in the application that you use without wanting to accept new features in the operating systems that you do not use.
Is that a correct assumption?
Oh, and like Rick said, if you represent some corporate consortium I guess it is not a problem if they are willing to make a donation to the project in order to maintain backwards compatability.