Microsoft showed they can semi-competently run a PKI. The end.
Now had the Linux folks stepped up to the plate early on, instead of childishly acting like Secure Boot was the computing antichrist, the story might be different. But they didn't. We only have shim because some people at Red Hat had the common sense to play ball.
I'd love to know if my machine has been compromised with early boot stage "meta-hypervisor" or not.
the promise of secure boot and trusted computing is backdoor-free boot.
what is in your eyes evil and garbage about that?
Boot from read-only media you control, or set up network boot from a source you trust - you have to trust the firmware anyway. Secure Boot itself is quite pointless.
If it's FLOSS wirh reproducible builds, your trust can be minimized, since the community verification is going on constantly. Also, your suggestion is quite inconvenient and cumbersome to use and set up.