Teams treat cloud like a faster data center instead of a different computing model. Banking workloads are not web apps - and lift-and-shifting a mainframe to the cloud buys you cloud costs with mainframe complexity.
The BIS just blueprinted a tokenized unified ledger and JPMorgan put a deposit token on a public chain - in the same week. The hard part for banks was never the blockchain. It is retrofitting core banking to carry programmable money without a big-bang migration.
Fiserv, Bottomline, and a core banking system each work fine alone. Wiring them into one payment chain is where projects go to die - and the difference between the ones that survive and the ones that become expensive lessons is a handful of boring resilience patterns.
Most banks modernize core-first and treat compliance as the finish line. With Fedwire going ISO 20022-native in July 2025, that order is exactly backwards - compliance is the foundation, not the finish.