It looks and works so intuitively.
Modern toolkits just do a lot of stuff that older toolkits didn't. Some times at the expense of not being as quick to get off the ground as VB was.
The original winforms implementation in the early 2000's was pretty close to VB in terms of efficiency but its warts were numerous, e.g. the DPI used in the designer view (when writing the code) affected what happens when you run it, and so on.
Which can make each app fit the appearance of the given desktop.
Old guis also had more accssibility features.
The only thing modern ones have going for them is animation and visual customization.
Other point is noted. But let’s compare the alternative:
1. Fiddle with a config file for each app for a week. Distro includes this in dark mode set. 2. Each app writes custom code to listen for and adapt to dark mode events.
macOS introduced system-wide dark mode a few years ago, but app developers had to recompile and opt into it. This was done so that they could adjust their artwork and overridden colors to it. Windows 10 added dark mode, but only for "modern"/UWP apps. Classic Win32 apps need to implement their own dark mode with custom themes/controls (like Explorer does).