I couldn't design a site like Hacker News, not in my wildest dreams. It's the essence of a site with everything supliferous taken away and that takes talent that I just don't have. It's less about "looking nice" and more about "ok can people who aren't me actually use this site?

Bootstrap really helps with stuff like that because it does a lot of heavy lifting for you (styled content, scaffolding, themed buttons, etc) and allows you to fiddle with that stuff to get the effect that you want while still making everything line up.

Now make no mistake about it people can still design awesome sites with nothing and people can definitely design terrible sites with bootstrap it's just that the bar for terrible is a little harder to reach if someone is holding your hand.

Also with regards to the whole "everything looks canned" I think that's largely a part of being on a site where bootstrap is very popular. I know I used a lot of bootstrap sites before I knew what it was and I was none the wiser but now that I used it too I see it everywhere.