that his 1907 steamer automobile will still be operational long after current electronically computerized cars become inoperable
Yeah, that's sort of argument is often heard, and to an extent, it's true of course.
It's also true that his 1907 steamer offers horrible fuel economy, drive comfort and virtually none of the functionality that we consider basic to an automobile these days. As a daily driver to get to work, virtually the entire Western population would probably opt for an e-bike over the 1907 steamer. At the same time, if you look at the number of interventions needed per 100k miles to keep the automobile running, I'd expect the 1907 steamer to actually not be such a stellar performer compared to today's offering.
Which is to say that it's kind of a moot point and the truth is, as always, kind of complicated. Yes, we can lament over the poor serviceability of much of today's equipment, but we need to keep in mind that there's a price we pay for the complexity that's required to meet the needs of today's marketplace. The naked truth is that overall, we tend to prefer products with high functionality and a brief service life over the opposite. And despite this enormous complexity in even the simplest compliances, if you were to determine the failure rate in relation to this technological complexity, you'd find that reliability overall has gone up in the past century - not just a little, but dramatically so.
Presumably software problems also play a role in newer cameras?
Depends a bit on how you define a 'software problem', but generally speaking, this is not really an issue from a repairs perspective. It's not common to see software become bug-ridden over time while it functioned well initially. If it happens, the underlying defect is in fact a hardware problem - see e.g. the problems with ROMs becoming unreadable in certain Jobo ATL processors. Sorry, I can't think of an equivalent in cameras, because to the best of my knowledge, it simply doesn't exist/hasn't occurred yet.
Currents and voltages are small, so nothing burns down like in devices that are connected to mains voltage.
I've had smoke come out of a Canon EOS1 once. I admit it was a tiny little sliver of smoke - but it was smoke alright.
Everything scales, including electrical faults. Tiny little voltage and tiny little currents can still burn down tiny little components.
As to repairs on high-tech/modern electronic-heavy cameras: I think the major share of faults that you encounter in practice are mechanical faults. Think of the Canon shutter sticky issue in the early EOS series etc. and the T90 repairs you've been undertaking lately on shutter/mirror magnets etc. The battery leakage problems are hard to qualify as an electric fault; they're mostly a special case of user abuse, really - storing away a camera for many years with batteries still in.