I don't think you've missed anything official and I think that the nuances are still a work in progress. Clearly, there is a very strong push to digital, and it is accentuated by the need for a health pass (also not yet explained officially). I believe there is a good chance we have seen the end of tickets that look like tickets (printed on card stock and so on) but I do believe there will be a non-mobile means of displaying your ticket. That may include a ticket you can print out at home and/or a similar printout you can get from the box office. There are various complications in the theatre that don't necessarily present at other venues. (For instance, TKTS.) So yes I think there will be a backup plan, but I also think the process will be slower (and especially when your vaccine documentation is added to the mix). For better or worse, I think we are quickly reaching the point where a cell phone will be essential for a lot less luxurious things than going to the theatre. I hope your theatre-going days are not over.