Yes, there are some consumers for whom those everyday services are everything and they'll go to some 'app only' bank that does that well and without excessive fees. From the point of a traditional bank, that's not a problem, good riddance - if they don't use other products and aren't willing to pay excessive fees for everyday things, there's no money in having them as customers, and when they'll want to do something profitable (e.g. take a mortgage) they'll come back from that app-only bank as that product (the financial product, not the tech product) is actually competitive.
Note: this is from an EU viewpoint. USA may have a bit different perspective as the regulations there allow quite a lot revenue streams (e.g. bounced check fees) from people with no money and no other products, in EU much of exploitative payment practices have become restricted, so these customers simply become unprofitable and not really desired, the main value of "having them" is that this might help you sell profitable products to them later when they have more money and/or more plans for credit.
Of course for very specific high-value transactions, it may be useful to talk to someone, especially when it's something that also involves advice, but most people only do that kind of thing two times in their life: for mortgage and pension.
Modern banking does not function without the app (be it web or mobile).
The 1st was the real product, the 2nd the nice-to-have
Obviously core tech in banking is infinitely more critical than an app but the point is the same; the tech in banks, unless its 'quant', HFT or ML is not the money maker and therefore won't be paid as such