It will be extremely difficult for Google to lose market share and that is because they have done a good enough job of fooling people over the years and spreading their wings in many directions. Their sheer dominance in the mobile phone market makes it a slam dunk because its very likely your family members or friends or friends parents and family use an android mobile phone and just use chrome because they have little sense at all.
This is no limited to older people. I speak to younger people that have absolutely no idea about tech stuff and the world that lives outside of default apps or whatever and they get frustrated even at the polite mention of a valid solution to their problems.