So now your computer needs to figure out if it should boot the bootloader either from firmware OR from disk. How should it know that? What would be a 100% reliable way to determine this?
And if there is a conflict (because now there can be conflicts. Oh boy!)... How should it be resolved?
Again, this is a source of even more complexity. All in the name of the "simple" solution you wanted. Just because a few MBs on disk.
Can't you see where this is heading? Do you really think this is worth all that extra bullshit?
While UEFI is clearly over-engineered in many aspects, what you're asking for is under-engineering. And we all know that leads to nasty stuff down the road too.