...
Take PDF for example. I think it being an ISO standard is a great thing and I would be pretty bummed if Adobe had arranged things so that no one but them could provide a working implementation....
At least the last time I was dealing with it, in the financial markets it's actually closer to the
BTC way. Several places had their own 'pretty' front end but the back end was all the same. The corporate users saw something different depending on where you worked, the consumers saw something different. The back end coding was from one place and it really did not change. BUT if you logged into your account from "A" brokerage and a different account from "B" brokerage you would think it was 100% different.
As for big pools and exchanges we are ASSUMING that they are on core we don't know if it is 100% the reference client or some heavily modified version of it or something else they put together. And for security they probably would not and should not tell us the truth.
-Dave