I haven't worked on a search product, but I've worked at small shops with bad search products (one's business was even that product).

Search is hard when you don't have lots of training data, data is poorly organized, you have mostly tail queries, and people aren't used to you search engine's quirks. Search results are also bad when you're balancing quality with yield (as in revenue).

Google mostly doesn't have these problems. It has loads of people searching for head queries, so results are continuously being tested to death. Website owners put some effort into making their content accessible to Google with SEO, and people are used to searching with Google, so they've learned a few tricks for less popular queries.

Local search and corporate intranet search have none of that. You're basically whatever Lucene does out-of-the-box.