Google seems much too sure of itself making this change. I hope their arrogance pays off just the same as Microsoft's did with IE.
I think it's part of a much bigger trend in tech in general but also in Google: Removing user control. When you look at the "security" things they are doing, many of them have a common philosophy underpinning them that the user (aka device owner) is a security threat and must be protected against. Web integrity, Manifest v3, various DoH/DoT, bootloader locking, device integrity which conveniently makes root difficult/impossible, and more.
To all the engineers working on this stuff, I hope you're happy that your work is essentially destroying the world that you and I grew up in. The next generation won't have the wonderful and fertile computing environment that we enjoyed, and it's (partly) your fault.
I recently quit my job, developing among others the means to "protect" media using DRM. While this was not a primary motivation, I'm glad to somewhat clean my hands.
The technology (dubbed Common Encryption) is a bunch of smoke and mirrors that a childishly easy to hack around. Yet clearly aimed against good faith consumers.