Imagine what it's like for people still running VB6 apps. A couple of things actually make it worse for them:
1. VB6 is no longer available for retail purchase. The only way to get access to it now is with a MSDN subscription. That doesn't exactly make it attractive to new developers.
2. VB6 was never updated for compliance with operating systems later than XP. As XP is being desupported, it becomes increasingly difficult to support VB6 apps on more recent operating systems.
For more info, see: VB6: The Looming Crisis
I also found this interesting. There was a time even when PowerBuilder was at it's peak when the number of VB6 job offerings dwarfed the PowerBuilder offerings. Here's some more recent data.
And then there's this. A company that offers training in "legacy technologies" (including PowerBuilder) so that developers who are having trouble finding a job or are not getting paid what they want can find jobs easier and for higher pay.