You could easily solve all of this without HFTs - you might introduce a few seconds of latency but virtually no real investors care about that level of latency and it would save them billions per year.
It absolutely would if you remove the cut HFTs take out of the market. I'm sure you'll make some argument about liquidity and spreads but, in the aggregate, the money from higher spreads goes to market participants so the market as a whole still saves by eliminating HFTs, even if the spreads go up a bit.
This is like saying if we eliminated millimeters from rulers, and only used centimeters, everything would get closer together.
HFTs do not take a cut out of the market, their cut comes 100% from other market makers. Those are the only folks who would benefit from eliminating HFTs, and unless you’re one of them, who cares?
I don’t care who buys when I am liquidating a position. That’s the whole point of a market. Therefore I don’t care about HFTs.
