The only fluids I have seen evaporate from a car are Coolant, at an extraordinarily slow rate, we're talking a couple of ounces a year. Windshield washer fluid I have seen evaporate; and probably worse I've had old windshield washer fluid freeze in winter, likely because the methanol in the fluid evaporate out of it to raise its freezing temperature.
When I lost petroleum based fluids, or brake fluid, it was always leak, it was just a matter if the leak was so slight it can fool you into thinking there might be another reason it was lost.
Keep in mind;
Disc Brakes, as the pads wear down the brake fluid level at the Master Cylinder drops. That is one of your indicators the brake pads are worn out, the brake fluid level is at min.
Engines do consume engine oil, even prefectly good engines with no leak. Its just the rate they consume it indicate if something might be wrong. And it can be other things causing the consumption other than a worn out motor, the PCV valve is a good one for causing the engine to consume oil.
Any car, you're not going to be able to go years without topping off at least some of the fluids, if not all of them. If you've got to add a couple of ounces every other year, why worry yourself, look for leaks or problems, but move on with life.
Adding incompatible fluid to a system can destroy seals. I think everyone has heard a story of someone mistaking a Brake Reservoir for Power Steering since it was so close to Steering Wheel. Then within weeks having their entire brake system destroyed, because the seals swell to 5 times their normal size when exposed to petroleum based fluids.
I don't know for the JGC Electric Motor Power PS Pump, but in most case with Power Steering, over the years they keep making more and more demanding systems that breakdown their fluids either through shearing or heat, and thus require a more durable fluid than past PS fluids.
Again I don't know for the electric ps pump, maybe they use seals that are incompatible with the ATF+4 used most FCA vehicles. But in most cases, when they recommend a special PS fluid, its because the PS system is more demanding/hotter running and will breakdown the fluid to soon. So if you use the wrong fluid, it might work just fine for a couple of years, till you need a new Rack and Pump because the fluid broke down to the point it caused the system to fail.
Seals on moving parts, like brakes and shafts coming out of the PS rack, can leak because of gunk collecting on the surfaces and causing the seal to leak as it runs over the irregular shaped gunk deposited on the surface. Gunk is usually the result the fluid breaking down or getting contaminated.
