No app, no account. I just send an SMS to a certain number, with a code for the kind of ticket that I want to buy, i.e. for a certain bus line or for all lines and the duration of validity.
The money is taken from the credit that I have at my phone company.
None of the problems described in the parent article can happen.
Far better are the systems popping up in Europe where every bus has a terminal that accepts any Visa or Mastercard. You can just tap and ride, no more tickets unless you need a monthly ticket. Generally such terminals even remember your payment, so you can transfer lines by tapping again but won't be charged again.
I have a prepaid card and I never had a subscription to a mobile phone company.
The only thing that matters for buying the ticket is to have a non-null credit at the phone company.
Though I agree that probably it does not work for foreign SIMs. Foreigners have alternative means, e.g. buying all-line passes for a certain duration, with a credit card, from automatic dispensers. Also the use of a credit card with the terminal existing in any bus, works.
Of course the SMS-based method is very old tech, but it is far more convenient than the procedure described by the OP for Munich. It is also more convenient than having to use the credit card every time you take a bus.
I cannot imagine any newer tech that would be an improvement over this.
That probably differs from person to person. Once I hit 40 and my eyesight declined, getting out my phone and sending an SMS is noticeably more effort than taking out my card and tapping (which I could do blindly).