What you're explaining is simply a difference in philosophy.
Why are you considering it "bad" to make a game with less depth and sell it for $5 rather than make a game with tons of depth and sell it for $60? Why is it considered "bad" to offer a costume pack for $5 instead of a 30-hour expansion for $30?
You may personally prefer the "more for more" concept (i.e. a $30 expansion pack that adds 30 hours of new content), but many prefer the "less for less" model (a $5 DLC that nets them one or two new missions).
It's like comparing sonnets to novels. I mean, sonnets are great, but are they as in-depth as novels? Of course not. But that doesn't mean they are crap, either. You can still sell a beautifully crafted sonnet and have a great time reading it, rather than spending a week reading a novel that was 5 times the price of the sonnet.
There's nothing inherently bad about offering smaller, less in-depth games for cheap. Just like there's nothing wrong with offering less in-depth DLC for cheap either.
The reason there aren't expansions is because maybe an expansion is not in the budget or feasible to pull off. It's easier to make smaller DLCs that offer less, but they are also asking less money for them as well. So it balances out.
And I definitely don't agree that large publishers don't give gamers what they want. They may not give you what you personally want, but I could almost guarantee you they give DLC that the majority of fans (be they casual, hardcore or in between) want. They can't please everybody, but it makes perfect business sense that they at least try to please the majority of players of their game. Otherwise they would quickly go out of business, no?
EA published one of my favorite games of all-time, Kingdoms of Amalur: Reckoning. And you know what that game got? 2 awesome DLCs that added 2 entirely new areas, new gear, many new quests and storylines, etc. They were well worth the asking price. And that came from EA. So I just don't buy it.