But Bitcoin needs a way to record and transfer these shares. Like colored coins. There are a bunch of contenders for which public blockchain will win. It will not be Ripple or Stellar. ETH is the obvious threat but they have their own problems right now.
Do you mean all the ICO's and erc20 stuff from basically 2017?
Yes.
The legislation to support the changes is coming. It will start in the smaller, more agile countries and spread into places like the US.
Problem is that even if they wanted to meant those tokens to be shares that would make the SEC involved. So, currently, those just useless tokens with no representation of ownership.
The SEC will be involved and will bless it. It will all be fully legit.
Blockchain makes it impossible to rehypothecate (hmm, not quite the right term, but best I can come up with ATM), so it will not be embraced for equities until it is forced on them. Ever tried to get a certificate for a stock you 'own'? Since the broker sold it to 50 different people (number out of my ass) and never bought it in the first place, it is next to impossible. But very, very profitable! If I can make time for it, I'll try to dig up some of the articles on it. Horrifying and fascinating at the same time...
Blockchain will be used for settlement not trading. So if you allow your cryptoshares to stay in your brokers’ account they may be lent without your permission. Not your keys etc.
Brokers (not exchanges) are most at threat of disruption. At least until decentralized exchanges stop being a shit show. Then the revolution really kicks in and exchanges go the way of the dodo too.