This is because a huge community of VB developers built up during the VB1-VB6 era, and then Microsoft blew that community to smithereens with the language and licensing changes that accompanied the move to .NET. VB still exists in the form of VB.NET, but in terms of popularity it never recovered from the diaspora of VB6 users who abandoned the platform and never looked back.
So today you have two groups with an interest in talking about VB: a huge community of VB expats who moved on to other languages when the crack-up came, and a relatively tiny community of VB.NET users who either stuck with the platform or came to it later on.
They stopped selling licenses for Visual Basic 6 through most channels when VB.NET launched in 2002. Not "warned that they were going to stop selling licenses," just... stopped.
So you had all these companies who had built up enormous codebases in older versions of VB, the last of which had been released only four years earlier, who suddenly couldn't buy the software all that code depended on anymore. Many of which were huge enterprises that were used to being able to phase out old software extremely slowly; so having the plug pulled on "classic" VB so abruptly was kind of terrifying for them.
Microsoft's official response to these customers was "VB.NET is much better, just use that." But you couldn't take a VB6 code base and run it under VB.NET without at least some modification to bring it in line with the new syntax. And VB.NET felt less like a version of VB than like C# with a coat of VB-colored paint on it, so the developers who would have to make those modifications faced the prospect of having to learn what was more or less a whole new language in a big hurry.
Since demand for client-server software (which is what you used VB to write) was in decline by then anyway, and apps that ran on the Web were the New Hotness, lots of VB developers decided that if they were going to have to learn a new language it may as well be one that let you deploy to the Web. So they didn't bother with VB.NET and moved to platforms like C#, ASP.NET, PHP, Python, Ruby, etc. instead, all of which had a better story for developing Web applications than VB.NET did. (Disclosure: I was one of these.)
Of those developers that didn't flee, most simply did the easy thing, which was to refuse to do anything; they just hung on to their existing VB6 licenses and kept on churning out VB6 code like nothing had changed. All that old VB6 code meant that you could actually make a good living for a surprisingly long time this way, just tending old legacy apps and keeping them running as well as possible.
So today you have two groups with an interest in talking about VB: a huge community of VB expats who moved on to other languages when the crack-up came, and a relatively tiny community of VB.NET users who either stuck with the platform or came to it later on.