I get that someone is buying someone else's stock but your comment seems to ignore the basic fact that even though there might be a limited amount of stock to b

I get that someone is buying someone else's stock but your comment seems to ignore the basic fact that even though there might be a limited amount of stock to buy or sell, there is an unlimited amount of potential transactions, which could result in an increase or decrease of the flow of money in and out of the market. Also, as another commenter mentioned you omit IPOS, SPACS etc...