What is it, do you suppose, that makes a hammered action arranger a difficult build/sell?

This is the keyboard that my cousin(plays 10+ gigs a week) uses. All of 20 some pounds...very acceptable hammered action for him...been playing piano since he was a kid.

https://www.sweetwater.com/store/detail/PX5S

He has told me that he would buy into an arranger like this in a heartbeat(my brother also)
were it a decent hammered action....even if it added 10 - 15 pounds...still gig worthy.

I own a Yamaha DGX 650...pretty good piano action..but pathetic arranger capabilities. Our church has a Clavinova...lovely hammered action...again, very average arranger capabilities.

So what makes it so difficult to produce a hammered action arranger, 25 - 45 pounds with decent arranger functions?

Yamaha’s CVP 709.. I’ve played it...wonderful keyboard touch(from a so so keyboardist)lousy arranger functions...and how much?