I agree. I think that those who feel that Linux should be a "main stream" OS (for whatever definition of main stream you choose) are missing the point that it was, and always has been, primarily a hacker's OS.
That's not to say that distros like Ubuntu don't have their place, but there's so much automation going on in these "modern" package management systems that you really aren't going to learn anything. Sure, you'll end up with a very nice, very functional computer, but that (IMHO) isn't the point of Linux. I'd go so far as to say that I feel like Ubuntu is no longer "Linux", just like Mac OS X is no longer "BSD". Based on? Yes. Is? No, Slackware is Linux.