I remember this slightly differently; the change to C# was swift and rather brutal, but VB.Net was very much the default choice for most organisations transitioning from VB. In 2001-2002, seeing C# in production eluded a response along the lines of "wow, you guys are quite brave, kudos". By 2003-2004 though, the switchover had pretty much happened, nevertheless there were still swathes of legacy code to be maintained. At least, this was my experience in the handful of companies I worked with around then.
I've seen several moderately large and active projects (5+ developer maintenance team) still surviving to this day, running on VB.Net. In most cases though, these were started in the mid-2000s, simply due to manpower questions, not language advantages. I recall being moderately surprised even circa 2008 that the author of CSLA.Net (an interesting object-oriented framework) was mostly using VB.Net. I guess from their point of view, they were more proficient in that languages, and the cost of switching was too high. I definitely don't see any rationale for benefits, akin to say F# vs C#.
That is how it was for my shop too but honestly I think the semantics of VB.NET was always closer to C# than it was to VB 6. I remember working on a mixed code-base and it was absolutely effort-less because the semantics and of course the libraries were all identical, you just had to switch syntax. Syntax isn't really what takes time to learn in coming up to speed in a new language; what takes more time is language concepts, semantics, APIs and tooling. Once you realize this and observe the fact that C# is winning mind-share there didn't really seem to be any need for VB.NET. It really seems to me like it should have been stopped entirely ~2006 but Microsoft just doesn't do that to products, to their credit in most cases.
Yes, I completely agree. Syntax can be a stumbling block for beginners, but is generally far easier to re-learn than core libraries, or semantics, etc. That said, the syntax shift from a basic-like language to a C-like language is slightly larger than what we are generally used to, within the C-like families. I recently had to work on some VB.Net code, and aside from the occasional "let me Google this quickly" moment for surprisingly basic concepts, it was a breeze for the reasons you mentioned.
I think the MS world of the time was very much a monoculture (and would be until circa 2010 or so), which lead to a lot of developers who had only ever really worked in one main language (plus maybe SQL / T-SQL). I tend to think this is quite similar to children growing up in a single-language vs multi-language environment. The patterns tend to get ingrained in your brain in the former, and there are few signals for our brain to understand that "this concept can actually vary from language to language, don't get too used to it", making later shifts much more difficult. It's kind of a case of over-fitting the data, which is the first language they learned, in this case. I think a lot of the VB and then VB.Net developers had this kind of strong mono-culture of language, which compounded the need to keep VB.Net alive for longer. This may have been further compounded by VB's image as a beginner-friendly language, which a lot of people took up to get into the industry as outsiders, without any formal or informal experience. I really do think this might be the main factor. VB.Net may have had a few tiny advantages in terms of semantics (slightly looser casting and conversion rules), syntax clarity ("static" vs "Shared" - an example of a keyword which is objectively clearer in VB, IMHO), or some convenience libraries (I recall occasionally having to reference core .VisualBasic assemblies to get hold of some helper method which was missing on the C# side, for no apparent reason). But it also had just as many detractors, and I would not think any of these were nearly enough to lead to people choosing it over C#.
I've seen several moderately large and active projects (5+ developer maintenance team) still surviving to this day, running on VB.Net. In most cases though, these were started in the mid-2000s, simply due to manpower questions, not language advantages. I recall being moderately surprised even circa 2008 that the author of CSLA.Net (an interesting object-oriented framework) was mostly using VB.Net. I guess from their point of view, they were more proficient in that languages, and the cost of switching was too high. I definitely don't see any rationale for benefits, akin to say F# vs C#.