Why to write well

I'm kind of grumpy about writing well. I don't mean "good writing," which connotes a superior style and wit, but simply writing well enough so your point comes across. It drives me absolutely bonkers when I encounter a piece of purportedly expository prose that leaves me more confused than when I started. It especially bugs me when the writer seems to be intelligent enough that I could and should have learned something from that prose.

Here's an example from the comments to an essay on how politics will play a key role in any adjustment of China's currency:

Two points the surplus may move elsewhere, but you are assuming that it will be saved rather than spent on investments. Spending which could increase trade, Global GDP growth, and the export industries of neighboring countries that receive further development from the mechanism that ensures China receives a disproportionate share of global investment breaking down, which is essentially mercantilism on steroids.

I'm sure the writer knows what s/he meant by that second, sprawling non-sentence, but I sure don't. I'm confident the writer is smart, too, at least about economics, so I would have liked to know what s/he was thinking.

From later in the same comment:

Rather than propping up, and developing en masse, via infant industry theory on a massive scale, competitors in as many industries as possible, over as short a period of time as is possible by the sheer size and weight of the financial repression mechanism which essentially delimits the development opportunities of other trade PARTNERS in the system. ould work, even able to be overlooked in a very small country of small size, essentially runs counter to balance in such a large player.

Nobody's going to pay attention if you explain yourself like this. Life's too short to waste it deciphering gobbledygook.

[EDIT: for grammatical snafu]