Instead, focus on the new stuff.
New dating sites are constantly coming out. Rank for those. They don't have nearly the SERP competition the big ones do, and many times the volume is there. My best month is over $30k profit simply because I had the only review page in the SERPS (for a short time) for something that overnight had a retarded amount of demand.
Imagine if True.com changed their name tomorrow to something like WeAreTrue.com. You wanna jump on those opportunities when you see them!