I think that part of the reason the top 50 E-Commerce sites haven't implemented these features is due to the fact that their impact may not have been demonstrated enough, and articles like this will certainly help address that and bring more attention towards solving them.

The other part of the reason is that these behaviors are difficult to build (IMHO). I admittedly haven't done much research on how to implement complex search features like these, but I bet that the amount of information regarding best practice or established patterns for these search types is lacking. Without that information, the skill level required to design them is relatively high.

I'd love to implement these features in my apps, I feel the frustration of the users. But what I'd love to see now is an article or blog post in response to this that pairs each issue or desired behavior with a pattern or solution.

Making the problem visible is taken care of now, but the development community needs to come up with and/or share the solutions.