Yes, the cost of (decent) wheelchairs is entirely understandable. A lot of the technology is comparable to cycles, but cycles that are manufactured to order in small volume and then ridden for 12 hours a day. If you imagine a what a high-end HPVelotechnick e-assist trike would cost, then throw in a bespoke motorised pressure-relieving seat and custom hand controls, and add the inevitable cost of someone coming out in a van to sort out all the teething problems because even the simple parts are obscure (and you can't take it to them because your wheelchair is broken), you can start to see why.