I disagree. From personal experience, I suffer absolutely zero lock in to Google's search engine due to their ecosystem. I use their docs, I have an Android phone, I use Gmail, and I use their search engine completely separate from any of those (regardless of any back-end tie-ins that Google performs to supposedly optimize my search experience).

I specifically go to google.com to search, ditto on my phone. Nothing in their ecosystem prods me to do so, and nothing in their ecosystem prevents me from using a competitor.

I use Google because it's vastly superior to any other search offering. Period.