<< Dust is the reason why it faces down, this ISA-PCI idea just makes me laugh >>
Well for one thing, when PCI was introduced a large number of computers were true desktops still so I don't think the dust idea holds water.
Furthermore, last month I was using a face up video card. Last year I was using a face up LAN card. And the year before that I was using a face up sound card. All ISA of course.