While I agree that building a great and relevant search experience with a Lucene-based engine requires lots of extra time and effort to get right, there are other non-TFIDF based solutions that provide a much faster path to great relevance with far less effort (https://blog.algolia.com/inside-the-algolia-engine-part-1-in...), and it's possible to have semantic ranking without too much machine learning (https://blog.algolia.com/promote-search-results-query-rules/). Not to discount the value of machine learning - we're finding that for specific usecases ML can be a very valuable way to help surface more pertinent content for individuals based on their profile/preferences etc. (https://blog.algolia.com/personalization-announcement/).
This may be along the lines of what you mentioned around "commoditizing" complex traditional search workflows. I'd be curious to hear more about what kind of use-cases you think are trickiest without SS.