That means you need engineers on call 24/7/365, which raises the cost. One of the nice things about ACH is that it's dirt cheap, especially compared to the credit card network.
For example, Stripe charges 0.80% for an ACH transaction, capped at $5 max. Some processors just charge a flat rate. A credit transaction is a whopping 2.90% + $0.30, with no cap. When it comes to my paycheck and bills, slow and cheap is totally fine.
On top of that, many banks don't even post transactions on weekends/holidays anyway. They'll remain pending until close of business on the next weekday. That's been starting to change, but still.
The banking system is built around store-and-forward and batch processing, with lots of auditing in between. This is a feature, not a bug. :) Sure, it could be speed up... but if you really need instant, there are already options that exist (debit, credit, wire). You just have to pay for them.
(Fun fact: Even the credit card system isn't really instant. The credit authorization goes through immediately, but the actual charge still takes 1-2 days to clear... and is often done in end-of-day batches. And yes, there are exceptions... but it's not the norm.)
Really, there's no reason for ACH to suck so much. Other countries have better payments infrastructure that costs less (to operate and for end-users) and is more modern -- and it hasn't imploded their banking systems.
Same day transfers have been a reality for a long time (at least in The Netherlands), the fact that it takes 3 - 5 days here in the US is absolutely insane.
Don't forget that many banks will still require that they fax you a form to sign which must be faxed back for large transfers. This + multiple phone calls to both the bank and the person you're trying to pay make for a fun time.
Sure, but most transactions aren't large. The UK system is convineant enough that I've had several occasions where people have asked me to grab some cash for them on the way to meet because it was easier to make an instant bank transfer than to make the detour to a cash point.
A team of 100 24/7 engineers amortized across the full amount of money transferred across i.e. Bank Of America or Credit Suisse's would cost a fraction of a penny per dollar, and it wouldn't require 100 24/7 engineers.
The costs of real-time ACH have nothing to do with engineering payroll, and everything to do with executive payroll.
Banking isn't expensive in the US because of engineering costs...
It's expensive because of greed
Enabled by a lack of competition and regulatory pressure. In Europe politicians, giant co-operatives, and partially state owned companies aren't afraid to join the debate when someone mentions credit card fees.
For example, Stripe charges 0.80% for an ACH transaction, capped at $5 max. Some processors just charge a flat rate. A credit transaction is a whopping 2.90% + $0.30, with no cap. When it comes to my paycheck and bills, slow and cheap is totally fine.
On top of that, many banks don't even post transactions on weekends/holidays anyway. They'll remain pending until close of business on the next weekday. That's been starting to change, but still.
The banking system is built around store-and-forward and batch processing, with lots of auditing in between. This is a feature, not a bug. :) Sure, it could be speed up... but if you really need instant, there are already options that exist (debit, credit, wire). You just have to pay for them.
(Fun fact: Even the credit card system isn't really instant. The credit authorization goes through immediately, but the actual charge still takes 1-2 days to clear... and is often done in end-of-day batches. And yes, there are exceptions... but it's not the norm.)