We simply don't know how browsers would have developed in the past years if Google did not have a monopoly. However, we know that monopolies are almost never good for consumers. Therefore, there is a high chance that in an alternative timeline, where one of the biggest and most profitable companies in the world did not have a monopoly on browsers, we as consumers, would have been better off.
Exactly. It's like the arguments that are sometimes made to that credit Genghis Kahn with creating an integration of the Eurasian landmass and rolling out administrative reforms. It doesn't tell us what the world could have been like if it wasn't steered towards consolidation, and it doesn't even pretend to morally justify the domination. It's an inevitable consequence of domination that no one but you has the power to roll out reforms or advancements of any type. Organic progression that might have happened anyway becomes something that only could have ever happened through you.
We simply don't know how browsers would have developed in the past years if Google did not have a monopoly. However, we know that monopolies are almost never good for consumers. Therefore, there is a high chance that in an alternative timeline, where one of the biggest and most profitable companies in the world did not have a monopoly on browsers, we as consumers, would have been better off.