When I read about the 30,000 cycles, I can't help but picture a mechanism which performs a "perfect" opening/closing cycle with equal force distribution.

How many cycles would that translate to when being opened/closed on the go by pulling on a corner? Or being used by a toddler?

That figure doesn't make sense other than from a marketing perspective. It is missing all the important engineering questions...

How many did they test?

What's the standard deviation?

What does the bell curve look like?

What are the test conditions?

What happens when you put this in the hands of an average user who does not conform to the test conditions?

Micro-USB plugs are supposed to be designed for a minimum rated lifetime of 10,000 cycles of insertion and removal. My experience has not had one last even 2,000 cycles before becoming unreliable, even for cables that have always been used in ideal circumstances (gently plugged in, resting on a table). As for ones where the device gets used while plugged in, moved around, occasional lateral forces on the plug, well, they’re generally just about completely useless before 2,000 cycles.

USB-C plugs are supposed to be 10,000 cycles too. The A–to–C cable that came with my PinePhone was dead at the C plug end within four months of daily usage with occasional somewhat-stronger-than-ideal-but-not-all-that-excessive forces being applied. A couple of other cables haven’t had issues so far.

When they say 30,000 here, I’d be surprised to get 3,000 before significant problems are apparent, and wouldn’t be surprised if I failed to get 300. I like the idea and want it to work, but don’t expect it to just yet. I wish they’d focus their effort on having two separate screens with a small gap between them rather than trying to straddle the hinge, because that would be somewhere between almost as good and slightly better, and much more likely to be reliable.

This is still early tech. Early generations of mechanically-difficult things are generally terrible. I can speak to the unreliability of the Surface Book hinge: I had four units (19 months with moderate issues by the end (mild battery pillowage, screen yellowing, several split keycaps) that led to warranty replacement; 8 months then battery 2 spontaneously died; roughly DOA; two years before battery 1 died and it was out of warranty and after only a little more use it’s now pretty much a brick, can’t even stay powered on and significant pillowage on both batteries), and their base/clipboard, base/power and clipboard/power connections (which were basically the same interface) always became not completely reliable well within a year, though they weren’t particularly troublesome until maybe fifteen or eighteen months. I do acknowledge that I used this hardware fairly hard, but it was consistently well under a thousand cycles before at least minor issues in the connection were apparent, and these OLED hinges are probably even more demanding.

I've had a couple of laptops where the mechanical hinges became wonky after a couple of years. Intuitively they should be a lot sturdier than a folding screen, but perhaps intuition is misleading.