Huh? It's a ranked retrieval model. Each result has scored a little bit worse on their relevancy function than the one above it.
To not trust that the results on page 1 are better than those on page 34557 is the same as saying that their ranking function does not work at all, which would mean that it's at best as good as random chance. That's clearly not the case, therefore I can trust that page 1 indeed has more relevant results than page 34557.
With that said, Page 34557 doesn't exist. And that's fine. The result count estimate is not based on the actual ranking that has taken place (at least not directly). It would be an absolute waste of resources to rank that many results. If you cannot find what you're looking for on the first page, then it's much easier to reformulate your query. Easier for you because it gives you more control over what you want your search results to be and easier for google because it only needs to rank a couple hundred results instead of a bajillion.