That said we do have a car and also use it a lot. I think it has a lot to do with the time sensitivity. If you want to go some place and it’s not a quick walk or a straight shot on transit, or if you are going to get groceries or other bulky stuff, then yeah the car is easier.
I think, though, the idea is if you design a place such that you don’t HAVE to have a car, then cars would be driven vastly less. For us that’s true, combined my family of five drives about 7000 miles per year, much of that on road trips from the Bay Area to Tahoe or Yosemite etc.
Yeah. A lot of people fear that a transit centered city means we're gonna take ALL the cars. Realistically I think most transit/urbanist advocates are aiming for a world with 1 practical car per family rather than 1 car per driving age member of the household.
Modern car seats and LATCH anchors actually make it fairly easy to bring a child car seat with you. I agree with you though, all this stuff is bulky and adds up to a lot of baggage. It makes sense to have a car for your child. But those cars create enormous problems, and car owners should be required to pay to fix them.
See also: food deserts
I find the opposite to be true. If there are lots of people walking, there will be lots of walkable services and businesses, so you tend to have a lot of choice.
Ownership of houses is usually diverse in dense walkable cities so it's really easy to just rent space at the ground floor to start a business. If you don't like it, move across the street.
Compare this to car cities. People drive their cars to malls. Malls are very much rent seeking. I've heard that they constantly increase rents of the shops so there would be churn - new shops to "keep it interesting" for the visitors.