Is this keywords competitive and why?

So we need few weak sites to be able to rank? This should actually be common sense. I am still not completely if in the last case google shows the authority domain because it really has nothing better to offer or it is how google ranks in the niche. Yet is is a safe bet to look for a keyword that has a weak siten in the top..

For example if few sites in top 10 got less than 1000 pages or low overall backlinks count or domain age of three or less years. Maybe it would be good to make a script that would check ages of domains in top 10 as this would be single the most significant parameter.