The likely future is where you'll be given a USB-C charger to charge your phone. If you have no phone or is broken, it will be the equivalent to having a strongly damaged passport. No fly that day, get a new phone, fly on another date, just like if you needed a new passport. The phone will be your ID, passport, credit card and everything. But since it will be all backed up in Google/Apple/Microsoft cloud, maybe you'll be able to buy a new simple phone near the gate, log in via fingerprint and facial recognition and go on your merry way. But also, once all this stuff is connected up in the cloud, maybe facial and fingerprint recognition will be enough to fly. NFC chips under the skin are probably too bad optics for the near future, but in one or two generations, attitudes will shift.

> I've never lost a boarding pass, but if you lose one, you can get it re-issued somewhere, right?

Yes, typically there's a fee for getting it printed at the check-in counter.