[dehrmann]

This is a weird question because they're so different. Google handles an incredible number of queries, has specialized code for detecting and handling different search intents, metrics for result quality, and AI systems to improve result quality. Popular queries and unpopular ones likely go through completely different code paths, and recent data likely has separate code path. In addition, Google has a crawler side that you have to remember. Pagerank is also less of a thing than it used to be.

Elasticsearch is a sharded search index.

It's a little like you're trying to compare a bicycle (or for this analogy, even a fire extinguisher--these things are just that different) and a firetruck. Sure, there are some similarities and some overlap, but a firetruck is massive and very purpose-built.