People love knocking Bitcoin here, but this is why the technology exists. No reason to continue letting these institutions run smoke-and-mirrors with everyone's money
You might also not want to have a public ledger of all the ownership interests.
It also doesn't exactly solve the problem. You still have the prospect of double spend, etc, until commitment/ledger settlement. And for high stakes transaction you probably want humans in the loop talking about what to do when these things happen instead of some automated policy.
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.