After more reading on Azure AD enterprise applications, I notice that even if the current team is long gone - an Administrator can assign a new user to the roll and let the application be managed.
I am in an environment where code is the infrastructure and we are using Terraform for deploying these applications. Currently I am having to assign "owners" to the application and building and deploying it. Ideally I am hoping, a service account or some other system resource can bulid these long-running applications. Didn't find anyway and having to add all the current devops members as owners seem to be the only way. Would like to hear if anyone else figured out a better way that I totally missed. Thanks in advance.