nobody ever complained about extra garage space for bikes, etc., even if there's no need for stairs...

A standard garage is 20x24, and that is on the small size to unusable for any SUV or truck. So yes, that size garage will get used for a single compact car. Not two. And nothing mid sized or larger.

^^what Mark Bischak said. Based on what I see on client visits, generally a garage that small will have a project car (typically an MG or an old Mustang) under a tarp on one side and rubbermaid totes full of holiday decor and the kids' old homework assignments and drawings on the other. And 2-4 cars in the driveway.

Not big enough for most vehicles.I have no idea what those measurements from garage are.

REVISION:

Park your project car beside all your rubbermaid totes full of holiday decor and the kids' old homework assignments and drawings on a large flat surface the distance apart you want them in your garage. Open all the car doors wide open and one tote width to the side of the totes. Measure the width from the added tote width to door tip. That is the minimum inside width of the garage.

It is too small for two cars. Someone will have to park in the driveway.