Splitting up "monopolies" won't create competition, especially in the case of vertical integration. What would help competition is intellectual property reforms, deregulation, tax simplification, occupational licensing reforms, etc. But almost everyone weaving the "evil monopoly corporations" narrative explicitly ignores practical policies that address those.

I agree that the primary cause of all this is government interference regarding barriers to entry. However, did the regulation help insulate these companies against competition in the first place or did they use their money and power once established to pass laws that would keep competitors at bay? Lobbying reaps disproportionate rewards---those CEOs who stick by their non-rent-seeking principles are leaving big money on the table and will likely be replaced by shareholders. (Econ Talk had a good podcast on this recently.)

Regarding trust busting, it is worth noting that these tech giants give an immense amount of money and support to the left. Might as well give Warren some bipartisan support so we can thrash them a bit---it would be sweet poetic justice to attack these statist zealots with the very government power they worship.