Google killed off comparison sites from the top of searches, if you can't find the comparison site it might as well not exist (or if it does it is spending tons on adwords to still be found).

search compare prices on bikes brings up no comparison sites

search compare prices on laptops brings up 2 comparison sites (one result per site)

search compare prices on watches brings up 3 comparison sites (one result per site)

search compare prices on software brings up 2 comparison sites (one result per site)

Problem is comparison sites spam the search engine listings pretty hard. It's only a matter of time before Google decides to do something about it...