I don't think any of those died because they were unfashionable. They died because the world/environment they were designed for changed or left them behind.
Flash was built for the world of desktop computers with a mouse, keyboard, and relatively large amounts of RAM. It was optimized for Windows/x86 but could also be made to run on other platforms and architectures. Even on Windows it was unstable and extremely insecure. On mobile its performance was atrocious and all on onMouseDown() events (the typical click event people used) just went nowhere. Flash as written also didn't tend to handle portrait aspect ratios nor window dimension change events well if at all. Adobe was also a terrible steward of the plug-in. They did not want to put the resources into making it good, they barely kept it up with security updates.
VB was similar in that it was designed for the unconnected 32-bit desktop world. Microsoft wanted to drop the VB6 runtime and just make the VB language hosted on top of the .NET runtime. It wasn't that the language was out of fashion, lots of LOB apps were written in VB in many companies, Microsoft was just uninterested in continuing development and had a new hotness they were pushing. VB.NET was an imperfect upgrade path for VB6 developers.
Flash died because the iPhone killed it because Adobe refused to work with Apple to make it more secure and more power-efficient. Ultimately it was Adobe's own-goal.
And Visual Basic was similarly a self-inflicted death, when Microsoft decided to make VB.NET incompatible with the previous VB6. But what was bad for Microsoft was good for the internet, as HTML+JS ultimately replaced VB6 for enterprise apps.
FoxPro I don't know about, though. Never approached Flash/VB in terms of popularity.
Flash videos and apps got easily replaced, and animations with HTML/CSS/JS, and those bite-sized Flash games basically got replaced with mobile gaming as apps.