It's supposed to force a minimum level of designed longevity - you also get Chinese companies selling on Amazon using random-string company names. They seem to just spin up a new company and kill the liabilities; this continuing to make electronics that go very quickly to landfill.
You should know, but its hard to impossible to know for sure. Apple couldn't even predict antenna-gate, and Samsung couldn't predict their exploding phones.
Yes, you should know generally how its engineered and designed, but until someone is holding the device, you can't be certain, the same way that a white-board design of an API doesn't have bugs like the implemented one. Companies build the product, then subject it to tests to simulate wear and usage, but sometimes the tests don't accurately reflect how people actually use it (see antenna-gate) or similar issues.
These are exceptions and of course they couldn't be predicted because if they could they never would have shipped.
The problem isn't a once-in-a-product-line huge design failure, the problem is that there is currently a race to the bottom in consumer electronics.
When faced with a $25 coffee grinder and a $15 coffee grinder people choose the $15 coffee grinder. However the $15 coffee grinder is made using cheap plastic gearing that the engineers know will fail within a year or two of normal use.
This is not that complicated -- engineers aren't stupid and materials science is incredibly mature.
So a eg. broken screen is still a customers problem, unless they somehow manage to prove in court that the screens were shitty and break under what would be presumed "normal use". That's why there are basically no ads showing stuff like "survives falls from 10 meters high" here.
If a 2 year warranty inflates your prices like that, you're doing something very wrong.