I don't have any nostalgia for old machines, I understand the 5- or 6-figure price tags were ridiculous, but I'm curious - in what way did Unix machines back then work poorly?
No comparison at all. Just every single interactive aspect of them was worse in every possible way and that includes I/O performance. At the time, in that era, people would babble about how much faster SCSI was, but the disks sitting in PCs were blazing fast in practice despite being attached by glorified joystick ports.
I love the industrial design of these pizza boxes, though. I didn't mind when I was running them headless as IRC servers or web hosts.
But yeah, complete white elephants at that point. Too little too late.