Circa 1999 one of the popular machines in my uni's computer club was the BeBox - it had a solid web browser, it was fast, it had the cool CPU usage indicator on the front, and it was *nix enough to compile most stuff or to work on assignments in ANSI C. And it was just so snappy, it could do more than one thing without getting janky.
A real shame that they faded out. I kind of miss those days with all the different and varied workstations – Be, SGI, DEC, HP, IBM, Sun, ...
Twenty years ago I might have liked that too, but these days I much prefer dedicated machines (MCUs like Arduino, P8X32A, R.Pico etc. or "single-board" (or rather "open-frame") computers like R.Pi, BBB etc.) for the acoustic noise alone (not to speak of power bill and electrical safety). USB or Ethernet (preferred for galvanic separation) on the PC does just fine to connect to those.
If you had a PCI card you would need some kind of external adapter or breakout box for the GPIO pins. Seems much more practical to have the board in the "breakout box" and connect it via USB.
I don't know about the prices but mixed-signal GPIO rigs for PCIe and USB are very common. Look at the "LabJack" for example. The LabJack U3-HV has almost exact feature parity with the geekport.
A real shame that they faded out. I kind of miss those days with all the different and varied workstations – Be, SGI, DEC, HP, IBM, Sun, ...