I think the assertion might even have been true for non-pathological cases 20 to 40 years ago. A company that chose Visual Basic or Perl would have had a much harder road than one which chose C# or Python. But i think the languages which have survived to the present day are all pretty close in productivity. Except C.
I've worked for a company with a large code base in Visual Basic .net. Product been in development since the 90's, with rich customer that only cares about their software doing its job. It's a surprisingly productive language combined with Visual Studio. Even though, as a language enthusiast, I barfed a bit now and then. Dev team would like to switch to C# but it would have been a multi-year effort taking away from lucrative feature requests.
that comment is probably referring to VisualBasic 6.0 which was not a dialect of C# like VB.NET but then again your product from the 90s likely started off as that
> A company that chose Visual Basic or Perl would have had a much harder road than one which chose C# or Python.
Based on what? Economics define where you go, not language. If company using Perl or VB has steady cash flow and their bottleneck is language - they’ll just rewrite when it makes sense. No amount of writing in C# or Python from scratch will save you if your product is garbage.