It depends against which runtime they are producing their code. The 3.0 runtime is different than the 3.5 runtime. Much of the new functionality is built on the 3.5 runtime. If they are compiling their code against 3.0 or 2.0 then they will lose functionality.But what are you comparing that to? If you've spent 10000 hours writing a NET app for the 3.0 runtime, you won't have the new functionality of the new runtime either. The difference is that people using a 4GL with a compiler can pay the vendor another $250 and hey-presto, this time when they compile it takes advantage of applicable new 3.5 features. can you do that with your existing NET code for $250?
"... They ne'er cared for us
yet: suffer us to famish, and their store-houses
crammed with grain; make edicts for usury, to
support usurers; repeal daily any wholesome act
established against the rich, and provide more
piercing statutes daily, to chain up and restrain
the poor. If the wars eat us not up, they will; and
there's all the love they bear us."
-- Shakespeare: Coriolanus, Act 1, scene 1
