It's also true there are many other participants with many other strategies to extract that value created by the companies from acquiring and merging them to collecting dividends from a balanced portfolio to day trading, but the reason the market exists in the first place is because companies that create value need their capital in order to do it. As you correctly point out, most of the actual trades are secondary market ones involving companies not in the process of fundraising, but those trades are still positive sum inasmuch as without liquid secondary markets, companies that create the actual value might have found it too hard to raise funding. The difference between being able to sell TWTR on IPO day or shortly afterwards and being forced to hold it until an Elon Musk comes along and follows through with its existence has a huge impact on its ability to raise funds and grow. On the other hand reducing the time between trades down to smaller sub-second microsecond intervals is - whilst useful to people trying to win at essentially zero-sum trading games and inflating asset prices very slightly - going to have a pretty minimal impact on whether companies create more value by raising more funds.