Moving from T+3 to T+2 is estimated to have cost the industry over half a billion dollars in technology and process re-engineering.

Honestly, that's minuscule compared to the flows involved.

I think it is legacy thinking more than systems. If we wanted to we could have a system more like European one, but for whatever reasons we don't care enough. The behavioral side of this is far more interesting than the superficial technical issues.

If that's genuinely the case then it's no wonder people are angry. At the scale of money involved legacy tech just shouldn't be an acceptable excuse.