Reliability is there to keep your things running smoothly during normal operations. Backups are there for when you reach the end of your reliability rope. Neither is really a good replacement for the other. The most reliable systems will still fail eventually, and the best of backups can't run your day to day operations.

At the end of the day you have a budget (of any kind) and a list of priorities on which to spend it. It's up to you or your management to set a reasonable budget, and to set the right priorities. If they refuse, leave or you'll just burn the candle at both ends and just fade out.