"Fatal to competition" is always overstated.
It's only 20 years ago, when Microsoft looked like an unassailable monopoly. It wasn't antitrust suits that broke that hold, it was technological change - innovation, mostly by Google and Apple and to a lesser extent Amazon, that left Microsoft in the dust, despite their monopoly position.
Remember 10 years ago, we all thought Google was basically the advertising monopolist? Now Facebook has joined them.
And the same will happen again. "Incumbent advantage" has a limited shelf life - it only lasts until someone routes around it.