Another few pages later, I looked up whether other people had the same problem. I was surprised to find that there was no issue with the Kindle copy. That's just how McCarthy writes. Although it's no secret, most people don't mention it -- somehow it had never come up in any of the glowing reviews I'd read. It's not been mentioned in any of the 30-ish comments in this thread so far.
Now, it's a little thing, so it shouldn't bug me so much. But it did.
When I read a work of fiction, I do not want to be thinking about the writer or his stylistic choices. My brain's little imagination engine should be cranking away, running the projector, imagining the characters speaking, moving, thinking, and feeling. Words from the page flow into it like fuel.
With McCarthy, the engine would snarl and grind every time I hit some ugly looking naked contraction like "werent" or "didnt", or a bit of unquoted dialog that I didn't realize was a character speaking until the end of the sentence. The projector skipped a frame, and for that moment I was no longer thinking of "The Man" or "The Boy", but involuntarily thinking of "The Author" and his smug need to be special, to remind me of his presence, to prove that the rules of language are beneath him.
Ironically, the justifications I have read for this style are that it's supposed to flow more naturally. Apparently punctuation is unnecessary, baroque, and only slows the reader down. Perhaps many readers agree with that, but I don't. I've spent most of my life reading English that was written according to standard rules of grammar, so it parses readily. McCarthy's "house rules" grammar does not.
That all leaves a question. I finished The Road and found it to be OK. Would I have loved it, had it been written in conventional style? Still probably not. But at least I wouldn't be annoyed at the author.