It's also the examiner's job to narrow the scope of rights granted by a patent to accord with the amount of innovation present. The output isn't binary, and there's some utility in letting weaker filings through the system. An absurdly narrow patent that's impossible to infringe (often called a "glamour patent") still yields over $10k to the US treasury and avoids an extended and expensive fight by the government over rights, that at the end of the day, are of no value.