From the outside it seems like the long term stock exchange was a flop. Why do you think it failed to gain traction? Is it that HFT just isn’t relevant to enough key decision makers?
Not sure I agree with your assessment. From my perspective, it’s actually doing well: appropriately funded, its proposal for companies to optionally move quarterly earnings to semi-annual is supported by the SEC, and it trades the same stocks as the other two major exchanges. But it takes time to build something new and innovative.