Interesting, I actually think that the indexing and the infrastructure part of building a search engine is much easier now than it was in the early 2000s. It's the ranking that's the hard part. PageRank helped put Google on the map and they've battled the hordes of low-ethics SEO practitioners ever since. I think it's generally agreed that PageRank wouldn't cut it today.

I tried Kagi as the default search engine for a few days and realized just how many little things Google does that I prefer, but never noticed until now. Not strictly related to search results, but things like converting units (Kagi has this, but it didn't always work), getting a time in a timezone (same), shopping results, the QA answers, etc. It's a ton of work to implement all that. For now I switched back, but I'll keep an eye out.