They really weren’t that effective with Microsoft then either. The antitrust was far too late for Netscape and allowed Microsoft to hold a dominate market share with IE until they allowed the browser to deprecate and Google came in with a much better browser and took over the browser market (and are now doing the same bullshit).
As long as we keep giving these companies meaningless fines or wait until the damage is irreversible companies are going to always push the limit and look at any repercussions as just a cost of doing business.