True, but many modern computers are using unified memory. On such systems all memory is almost equal, despite often reported differently.

For example, on my 5 years old laptop with integrated AMD GPU, windows 10 calculator in default state uses 33 MB system RAM, 9.6 MB dedicated VRAM. Maximized to FullHD screen, same app uses 36 MB system RAM, 13 MB dedicated VRAM. Maybe the OS counts VRAM as active private working set, maybe the app uses more than 1 buffer.

Regardless of the reason, it’s IMO unrealistic to expect a modern GUI app to consume less memory than required for the frame buffer for its window.