That's the thing. If we were to start from scratch building a stock market or banking system today, we might take different approaches.
But there's a market that exists at substantial scale that was originally built around T+14 settlement (and then T+7, T+5, T+3, all the way down to T+2 which is really still brand new). And while there's substantial risks and costs that come from delayed settlement, there's also substantial benefits... and an entire global financial system that relies upon the properties we get from these settlement delays. Another equilibrium being perhaps slightly better overall doesn't necessarily justify reinventing the wheel.
I suspect we'll get to T+1 settlement for stocks and many banking transactions in a few more years (we're already there for options)... and then it may be time to discuss the benefits of various types of "instant" settlement for some subset of financial activity.
But there's a market that exists at substantial scale that was originally built around T+14 settlement (and then T+7, T+5, T+3, all the way down to T+2 which is really still brand new). And while there's substantial risks and costs that come from delayed settlement, there's also substantial benefits... and an entire global financial system that relies upon the properties we get from these settlement delays. Another equilibrium being perhaps slightly better overall doesn't necessarily justify reinventing the wheel.
I suspect we'll get to T+1 settlement for stocks and many banking transactions in a few more years (we're already there for options)... and then it may be time to discuss the benefits of various types of "instant" settlement for some subset of financial activity.