Well, hard-coded styles don't get cached by browsers, so that's probably not the best example.
That being said, there are a lot of things people can do to improve performance that they neglect to. Sometimes it's just the pressure to get things done. Still, it's worth going back to revisit these issues.
Citation needed. I've seen evidence to the contrary. Generally anything with cache-control (or equivalent) headers suggesting that it should be cached, will be.
http://motherfuckingwebsite.com/
should we be hard-coding our styles into html and stop making stylesheets though? seems like a balance is needed