It’s so normal that I can’t actually remember it ever being any different. Even before the advent of mobile banking it was the same with internet banking. Instant transfers.

In Australia we’ve had free next business day transfers for as long as I can remember. Decades.

Transfers that clear in seconds are a relatively recent addition. It didn’t happen overnight, it happened gradually as bottlenecks were removed from the infrastructure. Some transactions were instant a couple decades ago, but it’s only in the last few years that most transactions are instant here.

I do this in the States. Maybe you haven’t noticed the option on the bank’s site? Also make sure to use a credit union.

In the US we have Zelle which is free and instant, but it’s still a third party your bank integrates