Earlier quoted context omitted.
What if Google can't decide which store is most relevant? Is it okay to use revenue as a tiebreaker?
Why stop there? Why just use it as a tiebreaker? Heck, why not only display links for people who pay you? Oh wait, you just stopped being (a) a search engine, and (b) useful.
Your interesting form of logic can also be used to condemn haircuts:
"Is it okay if I get a haircut?"
"Why stop there? Why just cut hair? Heck, why not have them cut your whole head off? Oh wait, you just stopped being alive."