A bike does make for difficult shopping for large families, unless you drag all the kids along on their bikes and they take a proportion of the shopping home!
But I live on my own generally and a bicycle is what I use for most of my transport. A lot of the time the journeys I make are the same time as a car would be. But you have to think about the costs of running a bike.
They aren't really that cheap. Needing new brake pads, sprockets and chain every year. Tyres can last a couple or more years unless the roads or debris slices them up. Things break. Having my own set of tools and the ability to build bikes from scratch (I don't just put wheels together, I've measured for spokes with new products and cut and threaded my spokes by hand before!) Things damage, like saddles, pedals. Rims eventually wear out, handlebars too.
And of course there is the physical side of things to realise. You don't actually start benefiting from hard cycling till you've been out for 15-20 minutes and in my city, it is hard to journey for longer than that!
At least I am ready if cars became so prohibitively expensive that most people couldn't use them. We are coming to the end of combustion engine use I fear.