The issue boils down more to consolidation of interest, and 'historical' thinking by people who can't be assed to understand how the market actually works.
Nasdaq and NYSE have significant volumes because people think they have significant volumes (as circular as that reasoning is). There are entire entities on the fund/investment management side of the industry that are content to do their entire risk adjustment (meaning, trading) in the closing auction, and the dominant closing auction is on the primary listing exchange (just because...well, as I highlighted above).
There was a brief period in the mid aughts when Nasdaq (through the INET and BRUT acquisitions) and BATS were able to compete with the more dominant NYSE due to monstrous discrepancies in system performance, but as all of the markets evolved over the last 15-20 years they are all (at least as far as the vast majority of market participants are concerned) effectively identical in pure technical performance.
Nasdaq and NYSE have significant volumes because people think they have significant volumes (as circular as that reasoning is). There are entire entities on the fund/investment management side of the industry that are content to do their entire risk adjustment (meaning, trading) in the closing auction, and the dominant closing auction is on the primary listing exchange (just because...well, as I highlighted above).
There was a brief period in the mid aughts when Nasdaq (through the INET and BRUT acquisitions) and BATS were able to compete with the more dominant NYSE due to monstrous discrepancies in system performance, but as all of the markets evolved over the last 15-20 years they are all (at least as far as the vast majority of market participants are concerned) effectively identical in pure technical performance.