That was actually a joke since I've never done any Jenkins consulting but Jenkins, including the setup cost is waaaay cheaper than other solutions I've seen for what I used it for: distributed cron, queuing system for tasks, higher level dashboard for managers, CI server, etc.
I could tell it was a joke when you mentioned keeping backups of your main configuration instead of porting ALL of your Jenkins config to code and maintaining that in version control.
At my current job I started as a SRE for the team supporting Jenkins and other CI/CD tools for the rest of engineering (around 50+ other teams), I moved back to a SWE position but as an insight: don't run a single master Jenkins for all of your teams, make it federated (per-team/project or whatever suits your organisational structure) AND do all of Jenkins' configuration through scripts.
Never rely on backing up the old configuration (problematic in cases of rollback to previous Jenkins versions, brittle for recovery), just start it fresh every time you need to recover and re-run your provisioning scripts, that also includes NEVER maintaining jobs through the UI, only through JobDSL, JJB or Pipeline scripts.
You need the team you're part of to have enough discipline for that. Not always the case. Sometimes you need to know when to cut your losses and go for the cheap, plastic, solution (i.e. backups).
