What happened to operators who just *knew* their machines?

Spent today replacing a thenostat on a 20-year-old Clark, and got to thinking about the old drivers I used to work with. Half of them could hear a problem a week before it showed up — a hiss here, a shudder there — and they were never wrong. Nowadays the lift trucks talk to a laptop and the young guys still seem to need the computer to tell them the truck doesn't feel right. Is that just nostalgia talking, or is there a way of knowing a machine that we're quietly losing because it can't be measured?