Some PC motherboards and laptops also have dual BIOSes/BIOS recovery[1] to prevent bricking. You can build a redundant system capable of surviving failures. Apple just doesn't want to spend the cost/volume of a couple 32Mbit roms, or however big iBoot is. Yes, simple is good, but it doesn't need to be this simple at the cost of longevity and upgradeability of the device.

Look at how much TLC NAND has improved in the last ~5 years, and ask yourself if QLC will improve as much. It probably will.

[1] https://www.dell.com/support/kbdoc/en-us/000132453/how-to-re...