Newbies or Better information?
"Established users do not create "better information"." - it's not about information being "better", it's about information complying with Wikipedia's stupendously complex rules for allowable content. Established users are much more likely to have read pages like WP:CSD and WP:NOT, or at least to know that Wikipedia has such pages and a user community to enforce the rules.
Certainly there are people not editing on Wikipedia who have knowledge that could improve Wikipedia. But their kernel of knowledge acceptable to Wikipedia is wrapped inside the much larger sum of human knowledge that we don't want.
For example, consider Wikipedia's baldly elitist stance against procedural knowledge. This pretty much excludes most of the practical knowledge of people who work with their hands. On Wikipedia, you are not allowed to share your knowledge of how to paint a house, grow a garden, repair a furnace, etc. Instead we want editors to focus on useless topics like Heraldry. This restricts Wikipedia editing to the leisured class, which can afford to spend its time thinking about things with little or no practical importance. People who work with their hands and live paycheck to paycheck will have a very different perspective on what matters, and much of what matters to them does not matter to Wikipedia.
I'm not saying this is wrong, just that it is. Wikipedia has evolved in a certain way. I don't know how to make it evolve in a different way. I'm pretty sure wishing won't work. Not many people in the world know how to build a top ten Web site. A lot of those people happen to be at Wikipedia. They seem to like Wikipedia the way they have made it.
I wouldn't argue that because Wikipedia is a top ten website, the people who have contributed to it are experts in how to build one -- or even know more than the average person about this trick. Offer a product or service which meets or exceeds minimal standards of quality for free (as in beer), & you will find a ready market. Wikipedia's success was due to filling this niche.
No one connected with Wikipedia should consider ourselves geniuses just because we managed to be at the right place at the right time. Not even Jimmy Wales. Although almost of us commit that logical fallacy. Including Jimmy Wales.