I suspect that if we could see what Google spends on hosting and other infrastructure we'd have a reasonable answer. Open source is not the same thing as "free

I suspect that if we could see what Google spends on hosting and other infrastructure we'd have a reasonable answer. Open source is not the same thing as "free to operate." Algorithms that choose results and assign them relevance/priority have to work on the indexed data, so there's more to it that just swapping algorithms.