That seems like a poorly run company. Idk. Maybe we’ve worked in very different environments, but devs have almost always been aware of the criticality of the app, so convincing people wasn’t hard. In most places, the answer hinges on “is it customer facing?” and/or “does it break a core part of our business?” If the answer is no to both, it’s not critical, and everyone understands that. There’s always some weird outlier, “well, this runs process B to report on process A, and sends a custom report to the CEO …”, but hopefully those exceptions are rare.