>
>If you're a VFP expert, it'll take you years before you can deliver the same quality on another platform.
>

That depends on the platform, and when and how you move to it.

I started moving to .NET around 2007 and wasn't at the some level of competence I had in VFP till around 2011.
There were two forces in play:
-.NET was a moving target- several "next great things" such as LINQ2SQL, et al came and went
-there weren't many definitive best practices- I'd go to .NET conferences that turned into arguments between experts on how best to do things, so you were pretty much on your own and I had several false starts.

The .NET target has been fixed now and there's pretty general agreement on best practices, so the learning curve should be based primarily on learning the .NET syntax- no easy task, for sure- but the whole process is a lot more straightforward now than it was 10 years ago.