This is definitely a huge part of it. My grandmother is not tech savy, and ended up with the google app installed on her phone. Because if she types anything into any of the search bars, google puts a big banner for the google app in the results page. She doesn't use safari for searching - she now goes to the google app.

Notably - it doesn't advertise chrome there? or maybe she just didn't see those. Most of her internet experience is through either the facebook app or the google app now