You may have left out a few items here;
Rent
Electricity
Plant and equipment cost
Shipping
Insurance
Administration costs
Advertising costs
other expenses
And of course you need to make a profit so yeah, it's not easy to make them on the cheap.
In my original post, I had many of these included, but I deleted them for simplicity.
When you add electricity, rent and equipment, you more or less get the production cost.
Then you need to add a significant markup to sell it to a shop, which then will need to add a significant markup to sell it to a customer, and 5 grand suddenly do not seem that much.
I do own a handmade bass that qualifies as a boutique instrument.
It is a wonderful feeling to have such a thing, where the profile of the neck is just like you want it and even the small details are just right.
But here comes the but:
While I still play that bass, It's not my number one at present. It's a snapshot of my Idea of the perfect bass when I was a few years younger. I have not yet stopped evolving as a bass player, though. So the Idea of the perfect bass is a fluid concept, ever changing with my actual state of development.