To answer the question posed by the OP, no I didn't think I would be doing the mileage I am now when I first started. I had no idea what I was getting myself into. I also had no idea that I would still be riding regularly after 29 years. I remember wondering to myself shortly after riding regularly if I would still be doing it in 10 years at, gasp, 36 years old. Most of us ride because it is a fun hobby and for the mental and physical health benefits derived from riding. That is the utility we get.
If using your bike as a mode of transportation to get groceries or whatever is the way you get utility then good for you. Both ways of obtaining utility from a bike are acceptable.
I am looking forward to hearing more replies answering the question posed by the OP.