Standard Oil, Ford, GM and US Steel to name four, dominated American life as much or greater than today's giants. Standard Oil essentially ruled the US economy, literally, for a few decades at its peak. Today's tech giants are comically weak compared to that sort of power and direct control over the economy.
Amazon in no way is dominating American life. Their retail sales are a third that of Walmart. They have lively competition in cloud computing, Microsoft is actively taking market share from them there, and Google is intent on competing aggressively (they can both afford to and have the technical chops to do it). If Amazon is lucky, one day they'll grow up to be as powerful in retail as Walmart was at its peak of dominance ~10 years ago.
Facebook is losing users in the US and that trend is almost guaranteed to continue. Competitors with appealing products will slowly siphon off users, new and old. Such platforms universally have an ebb and flow to them, they do not maintain peak power perpetually.
Google search is quite a bit less important than it was six or seven years ago. Their economic power is still slightly rising, their search product power is slowly fading. Microsoft knows that feeling, re Windows.
Apple? That one is almost pure bullshit. They've botched the home AI gadget competition. Siri is a mess. iTunes + iPod has lost its quasi monopoly. They have no dominant position in traditional computers. The iPhone is a juggernaut - so what. So is Boeing in airplanes and McDonalds in mediocre low priced hamburgers and Starbucks in coffee.