It's not what someone had to do to upend IE or that they will have to do to upend Chrome, it's what Microsoft didn't do to keep IE in power: they didn't do anything.
I agree with that completely, but personally, I seriously doubt Alphabet is going to let its flagship product's flag ship delivery vehicle falter like ie did.
I mean, who knows. Never say never, but they are going to be tough competition. Not to mention that browsers are becoming so advanced it will be tough for a small team to match the engineering prowess of a company like google.