Salaries for an analog circuit engineer, a digital circuit engineer, and whoever codes the driver and mixer app that comes with the interface (good engineers aren't cheap). Industrial designer who knows who to deal with thermal issues for designing the case. Federal income tax, state gross receipt tax, municipal business tax, franchise tax, sales & use tax, tangible personal property tax, unemployment insurance, social security and medicare contributions for employees, and probably some environmental and regulatory fees if you're manufacturing anything with nasty materials (e.g., chemicals). An accountant to deal with all this stuff. Medical insurance and perhaps other employee benefits. Commercial building space. Tariffs. Packing and shipping. The markup so the distributor has a cut. Software updates when Apple or Microsoft sneezes. Quality control. Marketing and design of trade show booth, packaging, and advertising. Web design and documentation. Customer service to handle returns and repairs. Liability insurance ("your interface fell on my dog and killed him so I'm suing you for a million dollars, but I'll settle for $10,000 if you pay me right now to avoid lawyer's fees"). Relocating when the lease is up on the commercial space and your rent is jacked up by 150%. Supply chain concerns that involve a capital outlay for parts that may or may not just sit on a shelf, or sourcing more expensive parts because they're all that's available, or doing a re-design to accommodate parts that are impossible to find or have tariffs that require finding a substitute.
Oh, and 85 cent op amps.
And here's a pro tip: Don't just measure noise and distortion. Inter-channel crosstalk is an important spec that separates the high-end from the low end. Also see whether electrolytic or tantalum capacitors are spec'ed where appropriate (yes, there's a big difference), and whether the ones that were chosen are known for long life. Oh, and if you're going to say "I can run 40 LA-2As on my native machine, so DSP is a scam!" - good for you if all your music needs is LA-2As, which are very forgiving on your CPU. Oversampled virtual instruments...not so much.
Remember too that high-ticket items don't sell in big quantities, so all the costs of doing business (and I'm sure I forgot a few) have to be amortized over a smaller amount of units compared to mass-market items. By definition, that means higher prices for high-end gear that most people can't afford.
So yes, in my opinion the video is labelled accurately as a total scam
