Pretty much all network code has workarounds or default configurations that work around problems with specific clients.

I guess this topic is more of a political issue rather than an obvious compatiblity issue, so it's not as clear cut.

But adding special code to deal with buggy clients is something everyone has to do sooner or later.

They shouldn't have to, but there are several examples of where it's the software author who has take action in order to put a stop to it.

Not an Apple fanboy, but Safari is a great example of software which has changed its default behavior to prevent creepy things from happening.

Safari is also a great example of a browser to keep the app store relevant ( outside of games)

Different companies, different incentives

If Google is going to shift to using almost unblockable tracking calculations, then servers are the next most logical place to push back against it.

Anyone who runs a site and wants to opt in against a default block should have to take extra action to reduce their visitors privacy, and should be called out for their behavior. As others have noted, there are already plenty of workarounds in use for many reasons... this is a BETTER reason than most.