At risk of nitpicking, why do say "controls" rather than e.g. "services" or "handles"? When you say "controls" it's like you're saying Google has some kind of monopoly power that makes it hard to switch. And yet anyone can easily switch to e.g. DuckDuckGo. If that's a monopoly, it's not quite the kind of a monopoly we should generally be worried about.
Browsers would be a different issue. In that case, there are network effects like about what standards are supported and how, which make it difficult to launch a competing browser, even with technological superiority, and in that case, it would be reasonable to worry about too much market share.
Browsers would be a different issue. In that case, there are network effects like about what standards are supported and how, which make it difficult to launch a competing browser, even with technological superiority, and in that case, it would be reasonable to worry about too much market share.