I'm guilty of that on a lot of tech sites. Who has time to read through hundreds of comments to see if your specific question has been answered?
However, I do quickly browse the first page, since that's where most answers are referenced or stickied. So I guess I would be OK here.
I do this a lot of time too. If I'm not active on the forum to meet a thread when it was created and I don't fit in on the first page, most times all I do is read through the OP, follow the first page comment, and then over to the last page comment and see the recent comments too. This is where if I have something to add to the table, I do that, and if I have nothing to say, I just work away.
In a thread of 1–10 pages, only a few members will have the time and energy to read through them all. That's just the simple truth. Unless the thread is really something of interest and there is simple information the person is looking for in it, it's not as if it's the best thing to do, but people just find it too lazy to do that as they want to focus their attention on other things. Most people prefer asking an already-answered question rather than going through the stress of searching for answers.