Okay - I'll start off with a bit of a historical perspective here ...
Historically, BASIC was always been looked down upon by the older generation of programmers who saw it very much as a toy when compared with the COBOL/FORTRAN/APL/RPG ecosystems of Big Iron, and it only came into its own (outside of DEC PDP) with the advent of the smaller microsystems.
BASIC was, most certainly, still a powerful competitor up until VB6, having had a distinguished career with Microsoft operating systems.
VB6 was the latest in a long line of powerful BASIC compilers that made programming Windows easy.
Unfortunately, with the demise of QuickBASIC (the free version bundled with MS operating systems) and the move toward C-like languages (BASIC.NET is in NO way VisualBASIC), and the rise of C/Pascal style languages included with products like Dbase, Clipper and Oracle, BASIC compilers began to wane in popularity.
It is interesting to note, however, that BASICScripting is still a part of Windows, and that VB6 is still a part of the MS Office suite.
Just as VB6 was maturing, there was an upsurge in the popularity of Apple personal computers and in Linux as an up and coming desktop operating system. Neither had a product equivalent to the Visual BASIC compiler available (nor is there a reasonable, cross-platform equivalent available to date).
At the same time, the explosive development of the world wide web saw the Java scripting language (another C-like language) take off. Again, there was no viable BASIC equivalent.
Looking back, it is easy to see that without the support of a major corporation like Microsoft, and without a single vision of the form that BASIC would take as it developed with the advance of technology, it was doomed to fragment into a mess of, essentially, home-brewed projects with great ideas, but little eventual substance.
There have been numerous attempts at filling the gap left by the loss of the Windows-only VB (Mono, Jabaco etc), but these projects have always ended up dead in the water, and the one web scripting BASIC equivalent to Java (Hot Tea - actually written in and running under Java) has sunk without a trace.
As it stands, there must be well ofer 200 versions of BASIC extant - a mix of interpreters and compilers - covering a vast range of capabilities and raisons d'etre, but they still share little more than their name.