Same-day ACH took a while AFAIK because of fraud risk especially to smaller banks and credit unions, although we've moved into phase 3 of the work last year so that's happening now. I think the push-to-debit functionality pioneered by the likes of Square Cash helped hurry this along but I'm only speculating.

It's not particularly insider information, the reason America was slow to the chip card game was pragmatic. The US is a very low fraud rate market, and re-issuing all 1.43 billion credit cards [1] and 14M payment terminals [2] was going to cost an awful lot of money. Further, major industry players like McDonalds weren't interested in seeing line speeds go down at point of sale as they switch from mag stripe payments which happen real fast to EMV chip transactions which, at the time, were really slow. Think <1s for magstripe to 10s of seconds for EMV. NFC helps mitigate this, but again, dual-interface cards (EMV + NFC + Mastripe) are a few dollars a piece.

tl:dr; it wasn't until a few years ago that the cost of the transition outweighed the cost of the fraud that would be mitigated as a result.

[1] https://wallethub.com/edu/cc/number-of-credit-cards/25532/

[2] https://gomedici.com/steady-growth-in-nfc-pos-terminals-in-t...