The main reason this happens is the importance of hitting specific launch deadlines. In the case of blockbusters like CoD, Battlefield, and Assassin's Creed, they're going to release during the holiday period no matter what state the game is in. A delay into December would literally cost them millions; a delay into the year after would likely cost much, much more. It's a jumbled mess but it's clear why they do it. The holiday launch window is just that important for yearly franchises.
However, I think we should be a bit cautious about including games that suffer from online problems only in this. I think part of the problem there is that online technology is still sorting itself out and many of the problems don't manifest themselves until you have millions of people hitting the system at once. I'm hoping situations like Drive Club and MCC are more inline with new system teething pains and that developers learn from those problems. I don't believe either publisher believed things would be so bad when those games were released into the wild, which I can't say about some of the titles from EA, Activison, and Ubisoft.
Yearly franchises with absolute-must-hit deadlines are the real problem.
