Unless you are specifically in the business of making financial institutions, it would seem that Stripe (and for that matter, nearly every payment provider that a computer can interact with) is open in all the ways that matter to a normal person.
> There are a number of cryptocurrencies which already have gateways baked in at a protocol level (such as Open Transactions and Ripple). However, there are huge network effects in any financial system, and to date these other systems have failed to win the necessary user support.
So you agree with the above—that as far as history is concerned, just being open doesn't get you adopted. :)
Bitcoin's crazy volatility and speculation drives "user support." It's ironic, because (1) the volatility is what makes Bitcoin unsuitable as a currency from the perspective of everything that matters economically (like your example, value storage) but (2) the volatility makes Bitcoin phenomenally successful as a currency from the perspective of user acquisition.
I don't know why it's so hard to promote transaction systems. Maybe there's some rule out there that no one competes on the basis of transaction fees, and those who do are shut out of the cabal. That's not a conspiracy that I subscribe to. Maybe the minimum transaction fee to make things economically viable is 2.9% of every transaction. So people do make platforms with lower transaction fees, but then they can't afford to tell you about it, or they don't manage to enrich themselves enough to make it worthwhile.
But Bitcoin, it managed to lie and tell us, "the lowest possible transaction fees;" while technically true, you just pay for the economic cost of promoting the platform and enriching its owners through its volatility.
In that sense, Bitcoin has been a terrific failure as a payment system. It's much worse to buy Bitcoin at the wrong time than to pay 2.9% on every transaction. But as a payment platform, as far as venture capitalists are concerned, it's fabulously successful. The early buyers of Bitcoin did enjoy a fabulous return.
User acquisition with negative cost to the platform's owners? Brilliant.