Actually such a world exists. MBR malware has existed for a while, and BIOS malware has already surfaced in the wild. That's the whole motivation for secure or trusted path booting in the first place.
If implementing this drives the creation of better BIOS/UEFI firmware, then all the better.
It's like saying that implementing a password system invites attacks on passwords, or implementing SELinux makes SELinux exploits a target. Well that is a truism. Any security mechanism will obviously become a target for those wanting to break it. That's not any reason for opting against one though.
Maybe Fedora should stop signing its distribution packages. After all, someone will reverse their secret key, and unless I am receiving mandatory updates I'm not going to be aware of this anyway