These wheelchairs are custom built to your dimensions. They're not adjustable one-size-fits-all ones.

There's another article by the same author about their quest to get a custom titanium chair paid for by their insurance - https://newmobility.com/finding-the-right-wheelchair/

It's really interesting to learn about all the variables that make a good chair - pressure distribution, the seat height, castor width, centre of gravity and other geometry variables. And all of those are unique to your body.

According to other comments here, a custom titanium chair costs about $4k, so $1k is cheap compared to that.