Now, I have no idea how successful a regular guy is without pick up or game at all, but I'd imagine if a regular Joe made an attempt it is probably somewhere around 50% opening rate with a 5% to 10% success rate for cold approach. I'd imagine that is also why most people get matched up by meeting friends of friends still.
I don't do strictly day game, but I can give you an overview of my success rate as I've progressed.
I got my start in college thanks to the help of two naturals and a willingness to do trail and error studies of my own.
Then when I finally found pick up material and started practicing it I could open 50% of the time. At first I actually went backwards. After a while I improved that number to about 80% of the time. Now, this was just using material word for word from the various books and systems.
My success rate at this time was 16% and was lower than before, but I figured it was just because I was paying attention to doing cold approach with all girls of higher quality (as before it was a mix of quality and mostly social circle).
After this I tested everything I came across and ended up tossing most of it out for a variety of reasons. I developed customized material and formed it into a simple system and today my numbers are:
80% to 90% of the time I can successfully open having a quality interaction and have a success rate of about 60%.
This covers predominately five areas (Farm Belt, Great Lakes, Appalachia/Southern Lowlands, El Norte, and Upper Coasts) from this map
http://www.flickr.com/photos/44769313@N03/
I also dabbled with online game for a while (30% reply rate (over the long term) with a very high success rate), but eventually stepped away from it because it was just easier to go out in real life.
Bottom line is pick a method that seems best suited to your personality (whether that's what I've come up with or one of the other guys), become proficient through practice, and then start tweaking to get the results that are right for you.
No system is going to be perfect and you will always have to face some rejection, but what you can control is how you react to it when it comes along. Most of the time it isn't even personal, but a matter of individual taste.