Because many of the apps require connections to deprecated (and usually non-working) Google APIs to even start up. Thus the white screens, crashes, etc., as mentioned in the article.
If you can find a way to emulate Google's infrastructure and services circa 2007, and redirect all your DNS traffic to this local infrastructure setup, then you may be able to run the apps in an emulator. But it's more effort than it's worth :(
Oh I see, well from that perspective quite a lot of things will go away, like I probably won't be able to emulate Gmail, $ing, all kinds of stuff, probably in 50 years. That doesn't seem to be a particularly Android specific issue.
gmail doesn't belong to you. With android, you wouldn't be able to run your own code without much effort/porting to new platforms. If you wrote a game for the amiga or apple, and still have the original machine, you can still run your own code. There are programs being used today that are 30+ years old which serve their purpose. This will be used to force extinction of programs.
If you can find a way to emulate Google's infrastructure and services circa 2007, and redirect all your DNS traffic to this local infrastructure setup, then you may be able to run the apps in an emulator. But it's more effort than it's worth :(