Loosing sight of the forest for this one tree.
1) Google doesn't release devices without unlockable bootloaders. They have always been transparent in allowing people to unlock their Nexus and Pixels. Nexus was for developers, Pixels are geared towards the end user. Nothing changed with regards to the bootloaders.
2) Google uses Coreboot for their ChromeOS devices. Again, you couldn't get more open than that if you wanted to buy a Chromebook and install something else on it.
3) To this day, app sideloading on Android remains an option. They've even made it easier for third party app stores to automatically update apps with 12.
4) AOSP. Sure, it doesn't have all the bells and whistles as the latest and greatest packaged up skin and OS release, but all of the features that matter within Android, especially if you're going to de-Google yourself, are still there.
Any one of those points, but consider all four, and I have trouble understanding why people think REEEEEEEE Google.
So you can't play with one ball in the garden (SafetyNet), you've still got the rest of the toys. That's a compromise I'm willing to accept in order to be able to do what I want to and how I want to do it. (Eg, Rooting or third party roms.)
If you don't like what they do on their mobile OS, there's nothing that Google is doing to lock you into a Walled Garden to where the only option you have is to completely give up what you're used to...
...Unlike Apple. Not one iOS device has been granted an unlockable bootloader. Ever.