The spot isn't really free. The spot has the same value as the spots they are auctioning. By not auctioning it off, Google pays an opportunity cost for the spot

The spot isn't really free. The spot has the same value as the spots they are auctioning. By not auctioning it off, Google pays an opportunity cost for the spot. Not that this even matters practically. I really don't understand people's obsession with this aspect of it. Google makes so much money from its search that there is no way that any potential cost to them from having to bid for this spot would have any real competitive impact on the search market. For default search on iOS, Google already pays Apple more per year than the EU fined Google on this issue.