$4k - $6k is a lot different than $8k - $10k when manufactures are considering all costs of building and selling a pinball machine.
If you think about it, the play field, backless, and boards are ALL reproduced already.
So you could build one from scratch or, contract the parts listed below as a manufacturer. You would just need to come up with the top and bottom metal play field parts+wiring harnesses. You could do this for just about any classic Bally machine, for which PF's+Plastic sets have already been made:
These prices are not exact and do not include tax...
PF $800
BG $200
Plastic set (if re-issued) $150
cabinet stencils $150
manufactured or "Donor" cabinet+tranformer $200
rectifier PCB $85
Alltek MPU $200
new Display set $249
S+T sound $150
paint: $100
$2284 so far... -not counting the stuff that's missing or tax(if you're building it yourself)- most of the missing parts could be made on the cheap in China...
You -might- be under 3K in manufacturing/assembly costs per machine (if you paid paid Stern to assemble the games or got your employees to work for free!)...
Not sure on the current license holder (Planetary?) and the other legalities regarding the industrial electrical approval costs and such. What about insurance to protect you against lawsuits and such?
Also, they are going to sell them for AS MUCH AS PEOPLE WILL PAY. Same as every single thing ever made in the history of the world.
The market may be there for a FEW sales but I just don't see it. Once 5 or 6 Bally's sell for over $8K... it starts to become realistic. But how many "classic" Bally machines would actually sell at that price? 40-60 for each title? Not likely... 500-1000? VERY doubtful...