manufacture them in quantity.
What's your definition of quantity?
Yes, you could probably get a worn out box brake and some hand tools for $300. Given some messing around, you could probably turn out 4 or 5 a week. And at $300 retail, that's almost worth it for a retiree.
The next step would be a good box brake (perhaps electromagnetic) and a CNC router. Call it $15k. With equipment like this, you could probably turn out 40 or 50 (working your a$$ into the ground). If you could sell 50 a week at $150, you would break even on capital and COGs at around 4 months, and it would be a tidy living at the 10 month mark.
Given that you probably don't want to invest in a CNC punch press, a hydraulic press brake, and the tooling to go with it (not to mention a lease on a building with at least 480V 3 phase), then the next option (really the first option) is to get someone with that equipment to do it for you. I'm guessing (not really) it would be around $41 a skiff, packaged...at a MOQ of 1000 pcs. At 10000 pcs, it could come in around $29. The *rent* on your lease is probably $15k a month, not to mention salaries for all those guys and gals to run your fancy equipment. A million dollars doesn't go very far.
Now, if you're Behringer, and you HAVE the machines, then tooling will probably set you back about $60k. After that, COGs is probably under $11. I'll bet packaging costs them as much as the product, for a skiff.
The *real* problem is another thing entirely...selling them skiffs to sparkly-eyed modular enthusiasts. If you're a builder-engineer-type (like me) then you suck at advertising, marketing, selling, collecting bills, and accounting. Imagine you DID turn out 4 a week...how are y'all gonna sell 208 skiffs a year, son? Reverb? eBay?
That's not to say there aren't opportunities...it just depends on your scale. And your budget.
I don't even think B are making skiffs for the money. It's simply a smart loss-leader for image and product enhancement. And frankly, that is the best argument for making enclosures at all. I think Intellijel took the most Intellijellint approach, and let their enclosures spawn an entirely new market. I'm also watching the janky-smart moves of Erica Synths...
And while those guys are making awesome tiny homes, the big B is churning out beigeville homes for the rank and file, and their shadow looms large.
Sorry, this went a bit off-track. You can tell I'm bored by the increasingly-long novels I am typing on Muffs...