alt Hacker NewsLicense changes - BSL or closing the source
If there's no money in it for them - reduction of staff or funding leading to slower releases and bugfixes
Moving some features like Spring Cloud / Spring Integration, or new development behind a paywall (think RHEL)
Big users (like Netflix, Walmart, JPMorgan, LinkedIn/Microsoft, etc) would likely be able to pay for it (until they moved off), but smaller companies and individual developers not so much
I think it would be more of a Redis situation - steward changes the license, someone large enough to maintain a fork creates one, and everyone moves to the fork. In Redis's case, Amazon forked it into Valkey.
Spring is so widely used that there are multiple "large enough" companies who could do this