William Henry's knives are sold like pocket jewelry in fancy stores to people who are not knifenuts. They are the only brand to try this marketing strategy and it's been working pretty good for at least 10 years. There's a lot of difference between a WH current production knife and the Fallkniven U1 and regular rich guys are paying for the WH product.
It's kind of funny you picked the Fallkniven U1 for comparison, since it is a copy of a William Henry Evolution line design of about 10 years ago. It was supposed to be an "affordable" gentleman's knife. WH discontinued this line of knives since it wasn't successful. The Fallkniven U1 is not too popular as well.
Whether or not you spend more than $100 on an EDC knife depends upon how rich you are combined with how cheap you are and nothing else. To some people $100 is half the cost of their T-shirt and some really rich people won't even tip the doorman.