Every patch delay puts more pressure on you and your team to fork the codebase and go it alone. You and your team sit down and promise you’ll rebase over upstream releases and everyone nods wisely. Then you skip a release, and another, and presto: you now you have Bank Redis or Bank Selenium or Bank Hadoop trapped on the last version of upstream before the fork but to which you can patch changes as fast as you like. I’d liken this to crossing an event horizon except the astronaut sees the universe freeze and fade away instead of the outside observer.
It’s possible to make it work if the upstream project either gives you a majority vote (or at least a substantial share of the vote) on project direction, or you’re working on a project large enough to have lots of corporate (ie funded, high velocity) stakeholders already.