Be it a Pilatus PC-12 or a 747, all aircraft are, in effect, hand built. Leaving aside development costs, the non-recurring costs are very high. Every operator wants a diffierent specification, for which new design drawings have to made, approved by the certificating authority, etc. etc.
In my days of selling aircraft, (about 20 yrs ago,) the base price was roughly calculated on the basis of $165,000 per seat for aircraft up to about 100 seats. All aircraft are sold in dollars, no matter where they are built. Add on the cost of BFE ( galley, seats, carpets, curtains etc.,) a fancy paint scheme, and it isn't difficult to see why they're so expensive. And if you want reallyexpensive (and heavy!) throw in a freight door.
I'm sure they're more expensive these days, but then so is an Aston Martin, and that's hand-built too!
Backpacker:
I can assure you that competition amongst aircraft builders is more intense than anyone imagines, even before you throw in the national politics! Try getting hold of a copy of 'The Sporty Game' by John Newhouse. This is an excellent (and true) look behind the scenes in the plane-making world.