LOL re Apple Maps (though I've really never had issues with it).Again, it's a beta. One should not expect complete functionality, nor using this software on your daily device. If GPS was broken in a public release, then I agree we'd surely see some media coverage on this.
Specifically regarding maps, I counter your argument with the fact that Apple Maps already gets you lost -- even with a perfectly functional GPS
Re the public beta: we all know that people will not be using "secondary" devices for this beta. They're going all in to get the new features as fast as they can. If the stock app is broken, or Siri Shortcuts is not fully baked, no biggy. If a beta user has a house fire and no landline to call 911, much bigger deal. This problem seems to affect a fair number of AT&T users on Intel modems (T-mob, too?!?). I think that may be too much risk for Apple unless they get this fixed in a DP3 before releasing PB1.