Your understanding of HFT is wrong as well. It's not all low latency arbitrage. It's also execution finesse, risk management and ML-heavy. HFT firms will still be extremely active under this new market structure.
“Very short time-frames for establishing and liquidating positions.” strait from the SEC: https://www.sec.gov/marketstructure/research/hft_lit_review_...
Now it’s true an individual stock may only see 5 trades per day from a HFT algo, but theirs more than just one stock. The larger pool of money sitting around waiting for those 5 trades the lower your ROI. So, the obvious strategy is to reuse the same pool of money to back multiple different strategies.
Anyway my point is that it's wrong to think that HFT are going out of business with this change because it's a fundamental misunderstanding of HFT. There's almost always an ML component and always an execution component and these two skills are going to be critical to profiting off the new market structure. Citadel, Jump, Tower, you name it. I promise you they will be all over this new structure.
I completely agree, and they are going to use the same tools. The question is if this change is a net positive trade for the economy, and that I don’t know but I have heard reasonable arguments in favor.