You think a lack of technology is what's keeping these giants back from innovating? There's a reason many banks still have mainframes powering large portions of their internals. Lack of new tech is not holding them back.
There are many reasons. Institutional inertia for one, a lack of sufficiently knowledgeable people another. Banks are not innovating because you can't get around them anyway. And personally I don't mind, I'd much rather have my $ parked with an entity that moves slowly and predictably than with some 'move fast and break stuff' outfit that gives me a heartattack 3 times per year by showing me a $0 balance and no support department to call.
For example, stock option agreements are usually pretty straightforward... until a termination date has to be decided on. How does the termination get put into the contract?
Though I suppose smart contracts could exist as an automation mechansim , but there's a "wrapper contract" that provides "real deal" legal protection against abuse?
Coincidentally, that's (part of) the role our court system plays in contract disputes; but there are other existing systems e.g. arbitration.
I think a good analogy here is to compare to American settlers. You're going to have a few waves: the explorers who move into totally uncharted territory and take on significant risk by using smart contracts. These are kinda crazy people who love the innovation, and I'd argue this is the majority of people in the space right now.
Eventually there will be the settlers, who start finding early uses for this technology that can significantly lower costs. Basically collecting on low-hanging fruit. J.P. Morgan, many finance companies, some savvy governments will step in to capitalize on easy wins.
Then there will be the long tail of normal uses. By the time the average company invests in smart contracts, there will be very well-understood battle-tested templates and toolchains for creating smart contracts, as well as consulting firms that are specialized in writing them for you with provable security guarantees.
Right now it's early. Your average company should not use smart contracts, that's a no-brainer. But someday the economics are going to make it a no-brainer for certain things, like incorporation, or issuing shares, or doing payroll, or complying with import/export regulations, or doing corporate taxes, or whatever it is that ends up more efficient through blockchains.