What would motivate a company like Google to pay top dollar for a niche, one-product company with no revenue like Twitter? The smart thing for an acquirer to do

What would motivate a company like Google to pay top dollar for a niche, one-product company with no revenue like Twitter? The smart thing for an acquirer to do would be to wait until prospective targets are tapped out and can hear the wolves at the door. It isn't like there's a lot of potential suitors right now. The era of large acquisitions is over.