I think you made a writing mistake at some point about the market cap.
( if I make 1 Trillion of some coins and sell 1 coin to someone for 1 dollar then this coin will have 1 trillion market cap.)
that means that the market cap is 1 dollar, not a trillion
But good investing skills. research is very important
If 1 coin is worth 1 dollar then 1 Trillion coins are worth 1 Trillion dollars.
if its worth 1 dollar yes, but not if only one coin is sold to someone for 1 dollar....its probably some misunderstanding in your content, the way you wrote it.
Im economics the last price highest paid kinda dictates the price for the whole coin. Yes it not the best that is why many people are calling for ways to make marketcaps better. Liquidity should be taken in account in ranking along with the last price. That way the flaw of last price is some what covered.