Well for banks there is competition (and largeest german consumer bank - Deutsche Bank/Postbank offers a non-smartphone based authentication device [0]). Not so much for government run railway.
Many useful features like verified by visa or Google Pay or Apple pay is not available.
If you are that anal then using railway does not need app. You can use a mobile browser or desktop. I have seen people show QR code from their computer too. For D-Ticket one can buy from one of the local transport associations - with Chip Card (I am using that).
What purpose does Apple Pay / Google Pay serve other than paying from your smasrtphone? You can use Credit Card NFC payments if you want tap to pay and enter your pin. That workflow is not much more difficult than using a smartphone. And if you prefer using a smartphone - well, don't complain that you have to use a smartphone to pay.
Isnt the aim to remove dependency on Google/Apple? EU should have forced Google and Apple to allow people to use NFC pay without having Google or Apple accounts.
If you talk about using NFC card. Yes, that is available.
Also people are dependent on Play or App store. DB does not offer the app for direct download.