Cables go bad, and require adjustment. Where your bus was located, and what conditions it was operated in most likely have had a huge effect upon it's longevity too. Particularly when compared to the DeLorean.
And if you think the DeLorean's slave cylinder placement is bad, stay away from Ford trucks. Or you know what, take a look and see the nightmare that is the concentric slave cylinder to better appreciate how the DeLorean got the long end of the stick when it came to hydraulics.
Getting down to it though, cables require allot more brackets and adjustment points to implement in a vehicle. So that can drive up the cost and complicate the installation. Whereas a clutch line just needs some plastic clips to hold the bent or molded tube into place. Hydraulic systems also do not require all of the tinkering and adjustment that cable needs. The only prep needed is to bench bleed the cylinder, and then just bolt it all into place. Connect up a pressurized tank full of brake fluid and just bleed out the fluid until all of the air bubbles and old fluid is gone. That's it. Sure, you repeat it every couple of years, but it really isn't that bad at all.
Cables can have other issues such as freezing if water gets inside, and then eventual breaking. Again though, that's a factor that also depends upon the operating conditions. If you're in the desert, you'd probably never see that kind of issue compared to living in the rust belt.