people sell their old cars because their economic value is high and storing them is non-negligible expense-wise also. The economic value of older phones is frequently low, in the drawer they go. People who buy a new latest greatest high end phone every year do not have a drawer with 10 old high end phones in pristine condition in it.
you are engaging in "motivated reasoning", but your motivation is to "plz plz plz find any way that socialism is a good idea, or at least reinforce the populist ideas i have about wealth". Trickle down is a description of an economic thing that happens. You've latched onto those words because it sounds like "a trickle" and that's a bad sounding thing when your goal is taking away Elon Musk's money.
The Reagan years were economically extremely good. Economists are interested in debating how much his tax policies led to growth, how much was putting the oil shock of the 70's behind us, etc. But it's an honest debate. The points you raise point to you spelling his name Ray-gun, a non serious approach to economics.
Elon Musk "hoards his wealth" because his wealth is bound up in shares of his companies. Tesla and SpaceX are valuable because of what the market thinks of their economic activity. You are engaged in a dishonest analysis of the ledger when you go down one side and take Tesla's economic activity as a "given" that's good for people and that's good because people are entitled to that, but then down the other side and say "he's hoarding wealth, economics doesn't work!"
as I pointed out before, I will point out again: none of this helps you to misunderstand what happens wrt the carbon footprint which is what I was talking about.