Looks do matter. It's not nice, or fair, it's just a fact of life. And not only in terms of picking up - better looking people are statistically more likely to get a job, be better paid, have more friends, be healthier (good looks has a lot to do with physical symmetry, which has a lot to do with health) etc. etc. The world is nicer to goodlooking people and they are generally happier.
As a general rule, if you are a 4, you can get a 4; if you are a 9, you'll be able to get a 9.
However, having said that, there ARE instances where a really hot chick will fall hard for a dog-ugly bloke. (It's even rarer for a really hot bloke to fall for a dog-ugly chick!!) And there are many reasons for this - people fall in love for a lot of messed-up psychological reasons, usually to do with healing past hurts. Which means there's always hope.
I have experienced falling hard into a serious case of one-itis for someone I would consider potentially the worst-looking person I had ever seen - and realistically, most people I know would rate me an 8 or 9. After initially writing this person off as definitely not potential, I got to know them as someone of amazing character, who was one of the funniest people I've met. So BEING an attractive person has a lot to do with personality.
The fact remains though that it is extremely difficult to get looked at twice if you aren't attractive. You will have to work a lot harder, be funnier, be better in bed etc. But it is never impossible.