Well... tbh you get used to it. Not spending all available cash on ships, taking ships with salvage gantries to get more from debris fields, being efficient in battle by deploying less ships, taking recovery skills, being careful when recovering wrecks, and even scrapping ships in an emergency are all ways of avoiding supply spiral/death.
Running out of money/supplies is the only way to lose the game. It can be a bit harsh at times, but there has to be some pressure on the player to keep the edge on.
My rules of thumb: always have enough cash on hand to resupply (amount depends on fleet size), and always have enough days of supplies to reach a settlement. If ships suddenly take damage and the repairs would push a fleet past its endurance, stop the repairs on that ship ASAP.