I consider the unified languages of the past to be VB6 and Borland Delphi as two successful environments that had many happy users who preferred to live inside that world and get things done without a lot of fuss. I know my friends when VB6 started to be disfavored by MS and they felt pressure to learn .NET refused to use .NET as it was just too hard compared to VB6. The reference manuals for .NET are 1000's of pages when you print them all out.

My measurement of complexity includes both the syntax of the language, and also how many library API's you have to learn.

Haxe, which has roots in an open source version of Adobe's ActionScript is an excellent product. I often consider switching to Haxe for the implementation of the transpiler as it would yield Linux support. I currently emit AS3 or JS code, but Haxe is a very strong possible direction in the future as Haxe has a lot of portability.

I don't consider C a unified language. It had no database, no drawing model, no event model, and Berkeley Sockets was a library added in to support the internet, that unfortunately did not achieve complete standardization. C is the most portable language, but it just a step above Assembler, and full of pitfalls.

Tools do wax and wane in popularity; they are all useful in certain circumstances, and the more generally useful the tool, the more it gets used. VB6 was abandoned by its owner MS, when Gates retired (Basic was his pet project, as it was the original foundation product of MS' fortune). People used it as long as they could (and some still do). VB6 didn't make the jump to the Internet, but it could have if MS hadn't tried to force everyone into .NET (which was very complex).