Bank security Grrrrr

Background: I am disabled and don’t go out much. I have a very old Nokia phone PAYG with very little credit on it (not a smart phone), which I keep in my handbag upstairs as I only use it for dire emergencies. Recently every online bank and building society send you a text by phone when you want to log in. I used to only use my landline number on these.
First time it happened I had an automated call on my landline, which has a call blocker, so I couldn’t ask who it was and it messed my phone up completely. Couldn’t make or receive calls. Had to ask a friend to come round (during lockdown) to sort it out. This was an emergency as I need my landline.
Now if I want to use online banking I have to go upstairs and get my mobile then come downstairs again, which takes me ages. That is if I remember to get it before I start my banking, if I don’t remember by the time I get downstairs the time has run out on my code.
Why do these places make things so difficult for disabled and elderly people and demand that you have the latest
technology?