I called Capital One to replace a card this month (either there's no online flow or it wasn't available to me). The default flow to verify my identity before they'd replace the card was to send a notification to the android app. My android version is too old. The alternative flow (which took them 20 minutes to figure out) was to send a text message with a link to an online ID verification service.

Is it COMPLETELY impossible that you could receive that link on a dumb phone, send it to a PC with a webcam, and then take a selfie photo and an ID photo? No. Is it likely to be an incredible hassle? Dear lord, yes. You can't upload photos, so you'd have to finagle with a webcame to get a shot of your ID on a surface followed by a selfie of yourself. Is it possible that in other similar situations, you'll be required to use an android app instead of a website? Yes, I've had that happen.

I think you are grossly underestimating the degree to which smartphones have become absolutely mandatory for many tasks.