The difference between Self-Publishing and 'Real' Publishing

To continue the topic that everyone's Kindle book is FREE (http://danijcaile.blogspot.hu/2012/12/everyones-kindle-for-free.html), I was thinking about the differences between Self-Published books (A) and 'Real' published books by Publishing Houses (B).
I have read 1000s of books so far in my life, of all types and standards, and in the last year mostly self-published books. In terms of writing skill, there really isn't much between A and B, except that the standard is a little higher in B...but that's not to say there aren't some real humdingers in A! AND there are plenty of bad books in B, books which are so bad I couldn't get past the first page. NO, I'm not fussy, I just don't see why I have to read regurgitated crap.
Other than writing skill, B has the advantage of marketing, distribution, advertising, money and backing (people who will push the book). Sure, group A has friends and family, but this is not the same kind of backing, they're not 'in the business'.
So, unfortunately, IMHO self-publishers have a real hard time...and don't I know it!