I have one of these. Actually I have the 2nd or 3rd one ever made. The lady that makes those was my doula for my second homebirth actually.
That does sound like a lot of money, until you see how much cutting and sewing, putting buttons on etc, that goes into them. And they're not made on some machine production line like the Land's End, etc.
Also, (at least the one I have) the fleece is the "good" fleece. It's not the crappy fleece I've seen in other baby snowsuites or fleece pullovers, etc. The fleece on mine is almost impenetrable.
I didn't take the coat on and off at all. I kept the blanket snapped on going inside and outside, and when we got into the car or the store, I took the blanket part off. It's not too hot indoors if you take the blanket part off and pull the hood down, because the entire front is then open to let out heat.
I live in ND and I found this invaluable. If you don't live in a really cold place, you can get by with a thin coat. But if you live in ND (we recently had temps of -40 F wind chill) you have to have something warm. And unless you have a minivan, you can't just the coat off before buckling without exposing them to an extreme burst of cold.
It was comforting to me to know that my daughter wasn't having to tolerate being cold, but yet being able to see those harness straps laying directly against her chest with only her shirt in between.
I shouldn't speak for her, but making ones with cut out feet for walkers should be no problem as that is actually what she did for her 4 y/o daughter.