Yeah, and sometimes one car is better than another car, even if they have the same engine ($5 wolfson DAC), because more love is given to everything around the engine.
If you just want to put together a cheap car with a good engine, that's a different thing from wanting to build a comfortable or speedy car with a good engine. Someone who isn't in the market for that extra level will just be a sceptic and say "this Audi is just a volkswagen with a prettier body", but if you sit in one you'll feel the difference. (not sure if Audi's have VW engines)
"More love" in this case doesn't have to mean more than maybe a retail price of $50 or so, to get a DAC with a frequency response so flat and a noise level so low that any difference to more expensive items is purely academic.
Digital to analog conversion is a solved problem, with inexpensive commodity parts. Even if you buy an expensive DAC, the studio gear used to produce the music you listen to has gone through dozens of A->D->A conversions, all done using standard commodity parts. No one builds fancy audiophile-approved DACs and ADCs into mixer or studio gear.
In my home setup, I'm using a DBX DriveRack PX as a DSP EQ and crossover between my main monitors and subs. It's almost a decade old, but its signal/noise ratio is on par with the newest gear you can buy. Any competently built pro gear from the last ~10-15 years with 24-bit conversion can be plugged right into any analog signal chain and be 100% audibly transparent.
People worry way too much about the electronics, and way too little about their speakers and rooms.
You think they're overpriced, but I bet you no one is getting (very) rich off these $400 DACs. Even more, I think many of them profit so little every once in a while a company pivots or goes out of business.
An Audi also has just a couple thousand of extra love worth of physical cost added to it, but the retail price is easily upwards of $20.000 above the equivalent VW car. That's because if you sell fewer units, the r&d and marketing costs per unit are much higher, as well as the required profit per car sold.
If you get a good deal on your hardware, you might have that good DAC in a nice box with a pretty manual for $50 physical costs, then put it on a prime shelf in a nice Hi-Fi store for $130 (30% of $400), maybe $50 to target and prime your customer, and then use $150 to pay your audio engineer, your CEO, maybe outsource the rest of the company infrastructure, and then 8% interest to your lenders. That's 1.7M profit at 10.000 units sold (assuming that you do all of this within a year).
I have no idea if 10.000 units is close to reasonable for an indie hardware startup, but calculations become a little more complex if we're going to have to take a multi year ramp up in account..
edit: Sorry I got caught up a little in the startup aspect of it. Your system sounds great, but your DAC (and DSP+crossover system) also cost $400, so you're not making a point?
No one is getting rich off DACs, except for the makers of outrageously overpriced 4- or even 5-figure retail price units. After all, DACs are commodity hardware, boutique devices serve primarily serve as audio jewelry, with no technical benefit.
The DAC I use cost less than $30, yet performs well beyond the limits of human hearing. The DriveRack did have an MSRP around $300 when it was new, but usually $200 on sale, but it does do a whole lot more than a DAC, and the base price level for pro gear is somewhat higher than for consumer gear.
As I said, people focus way too much on electronics, when even basic devices are more than good enough. I don't even have to use the DAC anymore, after I switched to DisplayPort for my monitor, which has a perfectly good analog stereo output. The only reason I keep the Toslink DAC hooked up is pure laziness.
If you just want to put together a cheap car with a good engine, that's a different thing from wanting to build a comfortable or speedy car with a good engine. Someone who isn't in the market for that extra level will just be a sceptic and say "this Audi is just a volkswagen with a prettier body", but if you sit in one you'll feel the difference. (not sure if Audi's have VW engines)