I see a lot of internal pages at the top of google for certain low popularity keywords (~200,000). When checking how many backlinks they have, there are a lot, but they are all from other pages of their site. How easy do you think it is to beat these sites in the SERPS?
It would depend on the overall authority of the domain in question. Wikipedia pages can rank well with primarily internal links, but sometimes they can be tough to outrank. If you made an effort to get lots of quality external backlinks to your own internal page, it should be relatively easy to beat them.
If they pages don't have alot of external links to them, they shouldn't be too difficult to outrank. As for Wikipedia, they usually have lots of external links to go with their internal ranking, which is why they are difficult sometimes.
Yeh people forget that sometimes. They may have 2,000 good external links. but they are hidden amoung 200,000 internal links.