I agree- it would be a difficult decision to rewrite working code without a compelling reason. I could expand that point, but lets not go there for now. ;-) We could also observe that people in this forum considering NET are facing a rewrite anyway, so the opinions of those with "existing significant investment in older NET iterations" aren't so compelling.

Agreed.

FWIW I can report my own experience (anecdote) which is that C# code written 3 years ago is increasingly difficult to maintain because people seem reluctant to work with its older ways.

Out of curiosity, what specifically is difficult to maintain? (I don't disagree that older aspects of .NET 1.1 can be a pain, just curious what specifically you mean).

Can we agree that unless people are able to do it all themselves, the ability to support superseded methodology must be a significant driver.

yes, i agree.