There is no basic firmware maintenance to do. Firmware is supposed to be properly engineered, immutable, still to this day sometimes physically wired as 1s and 0s. It doesn't make sense to have expiry dates carved in stone.
Firmware needs maintenance because unless you're doing stuff for the aerospace industry, you're not mathematically proving that your firmware is bug-free. Eventually someone will need to install updates.
Well-written firmware doesn't need to be updated for the key database to get updated. However, some vendors messed up and now require firmware updates, while others simply store the new key in NVRAM.
Not to mention that firmware updates are often necessary for things like supporting new CPUs. Immutable firmware means that your system can never improve or expand to support new hardware, and I would hate to have to buy a new motherboard to support a new CPU.
You shouldn't need new improved proprietary software to support new hardware, that's just wrong. They're just bundling free apps into hardware at that point.
"New CPU needs a new software" shouldn't be an excuse to just let CPUs becoming its own computer with the real CPU you're paying for as one of many features. That's just fundamentally wrong.
