Then why do they want Google's search index?
The more crawlers out there, the more useless traffic is being served by every single website on the internet.
In an ideal world, there would be a single authoritative index, just as we have with web domains, and all players would cooperate into building, maintaining and improving it, so websites would not need to be constantly hammered by thousands of crawlers everyday.
One more crawler for a search index wouldn’t hurt.