Hiring a UX-designer is expensive. Not hiring one can cost you more
One of the benefits of having a UX-designer on the tesm is to make sure your clients get what they want/need and also develop a product accordingly. In the end I guess it is a matter of calculating the $100.000 salary, equipment, hardware,software,benefits,pension,electricity,insurance and lunch vs. Maybe not banking in more than that on income from clients.
As you say, software makes sketching functional prototypes easier and the client can even do it themselves. What they often lack is the background research part. It is easy to make a prototype, but knowing why you have this functionality over the other is the UX part.
It might be easy to overlook that a great peosuct need great UX. Will we need to rebuild the status of UX? Do we need to enter the pit of bad services before we reel it back up with UX? Only money will tell…