I had a PC I built and moved to a bungalow near the beach. Within the year it's power supply had rusted. My last PC in a relatively arid environment lasted 4 years.
It's probably the "sea" environment that would pose corrosion issues.
Power supplies are usually plated or coated recycled "chinesium" steel. This is because it's incredibly cheap and has a half decent EMC outcome for the price. One little nick in the coating or plating and that's it though. Really they could use other materials such as cast aluminium, brass or copper but they are orders of magnitude more expensive.
If you look at some of the older electronic test equipment which was made with much higher standard materials it's not uncommon to find something that has been in a damp shed for three decades and powers up just fine after the dead spiders have been removed and the mould cleaned off. BUT at the time of manufacture they cost more than a mid-range car.
In an interview on Radio Scotland, the project lead said the container is sealed with an inert gas replacing the air and with a significantly lower water vapour content than the atmosphere.
There is a stark difference depending on which sea you are located at. I used to live close to the Atlantic ocean, near the equator. The failure rate of electronic components was through the roof. Random memory failures (due to contaminants in memory contacts) as well as corrosion in copper traces in the PCBs. At least one instance of motherboard fire.
I'm now close to the Pacific. No issues whatsoever.
It's probably the "sea" environment that would pose corrosion issues.