Don't put all the blame on Apple here, I've never yet seen a contact manager that works the way contacts really ought to work. None that I have ever seen allows you to define things like addresses, phone numbers, e-mail addresses, etc independently of each other and of people, and allows you to create connections between them. I've often thought about creating such an app, but have never had the time to do so. I did try my hand at one point at creating such a database in FileMaker, only to find multiple obstacles thanks to some of FileMaker's quirks.
Of course, it couldn't hurt to suggest this sort of thing to Apple:
You're quite right that this is not Apple's failure alone, but I keep hoping they will think different. And on the issue of exporting Contacts data in a format that other, more capable programs can use, Apple is actively unhelpful, giving very limited tools and absolutely no advice.
Thanks for the feedback link. I used it just now.