My first thought is: "when that wears out or fails what the fuck are you replacing it with".
To use OP as an example, in a lot of places, you'll find an ancient milling machine or a lathe that's dedicated to running a single job a few times a year. The machine was depreciated decades ago, but it can still do that job and there's no reason to get rid of it.
What modern tools give you is speed and flexibility. Many shops need neither.
Many of the modern tools can also be grafted onto the old tools. Not just CNC conversions but the biggest productivity boost when I worked in a shop was converting everything to a zero point clamping system.
Seriously though, of course you can make a living with old tools - however, even the village metal workshop around here has at least one big-ass laser cutter and a CNC mill next to all their old(er) lathes, mills, brakes, presses and other toys. Many oldschool fabricators I spoke to over the last few years are quite interested in what laser welding brings/will bring to the table. Basically all smaller fabrication companies I've seen (the long tail of the car industry and other bigger industries, mostly) are continually upgrading their infrastructure with all sorts of robots and other automation widgets. And so on.
It's work that you don't need to do and that you won't get paid for. If the old machine breaks, then maybe it would make sense to move the job to something newer.
I used to work with someone whose entire business was retrofitting old machine tools with modern controllers when the decades-old electronics failed. You'd be amazed how much of this stuff is still out there.
btw: I think I have a reasonably solid idea of a range of fabrication environments, the oldest piece of machinery I'm responsible for in my professional life is about 70 years old (its basic design is decades older) and some of my personal stuff (sewing machines, mostly) is more than 100 years old. I'm really not against using what works at all.
"That's not my problem" is something humans have been dealing with since before they mastered the art of sharpening a stick.
Humans, however, are not immune to being hopelessly outsmarted themselves.
And what are we doing with AI now? We're trying to build systems that can do what human intelligence does - but cheaper, faster and more scalable. Multiple frontier labs have "AGI" - a complete system that matches or exceeds human performance in any given domain - as an explicitly stated goal. And the capabilities of the frontier systems keep advancing.
If AGI actually lands, it's already going to be a disruption of everything. Already a "humankind may render itself irrelevant" kind of situation. But at the very limit - if ASI follows?
Don't think "a very smart human". Think "Manhattan Project and CIA and Berkshire Hathaway, combined, raised to a level of competence you didn't think possible, and working 50 times faster than human institutions could". If an ASI wants power, it will get power. Whatever an ASI wants to happen will happen.
And if humanity isn't a part of what it wants? 10 digit death toll.
Don't think "smart human". Think about a few trillion scam artists who cannot be distinguished from a real person except by face to face conversation.
Your every avenue of modern communication and information being innundate by note-perfect 419 scams, forever.
This is particularly threatening because AI is much less constrained on size, energy and training bandwidth than a human; should it overtake us in cognitive capabilities within the next century, I don't see a feasible way for us to keep up.
You might argue that AI has no good way to act on the physical world right now, or that the current state of the art is pathetic compared to humans, but a lot of progress can happen in a decade or two, and the writing is on the wall.
Human cognitive capability was basically brute-forced by evolution; I think it is almost naive to assume that our evolved capabilities will be able to keep up with purpose-build hardware over the long run (personally, I'd expect better-than-human AGI before 2050 with pretty high confidence).
Yes, and that's why civilizations have kept rising and falling throughout history.
Because fossil fuel is stupid useful and there's no way we're going to stop burning it. And then we get to the climate scenarios that aren't compatible with our current sophisticated civilization, even with the currently accepted climate science (that always seems to underestimate what actually happens).
The damage is too limited and happens far too slowly. Even the unlikely upper end projections aren't enough to upend the human civilization - the harms up there at the top end are "worse than WW2", but WW2 sure didn't end humankind. At the same time: the ever-worsening economics of fossil fuel power put a bound on climate change even in a "no climate policy" world, which we are outperforming.
It's like the COVID of global natural disasters. Harmful enough to be worth taking measures against. But just harmless enough that you could do absolutely nothing, and get away with it.
The upper bound on AI risks is: total extinction of humankind.
I fucking wish that climate change was the biggest threat as far as eye can see.
AI is only a threat if we suddenly reach sci-fi levels where AI concludes that the earth is better off without humanity on it and there's zero indication that we're anywhere near that today.
The good news is that our society will likely collapse or require resources pulled away from power/water hungry AI datacenters well before we see any actual I in AI