A $2,000 barely running junk car is still many times faster than any human can achieve on a bike.

You need space, room treatment, and a fixed listening area for high-level room audio solutions. I can bring a pair of cans to anywhere I visit. Even with my desktop setup, I can listen at my desk, sofa, or armchair with an extension cable.

FWIW, I think there's plenty of differentiation at the high end if you know what you are looking for, and willing to build an appropriate system around a pair of high end headphones. You can also make $500 speakers sound really good with treatment, so the cost point isn't clear either way.

>Speakers are way better than headphones in my experience and I don't know why people buy these very expensive headphones instead of speakers at the same price bracket.

I wouldn't say they are better. Maybe better in the sense that a car is "better" than a bike, but if you want an absolute top shelf bike, that's still $20k or more.

No need for a matching box. If you watch your volume, direct wire from the taps is best.

Cheap speaker amps might have a higher noise floor, but the higher end stuff is almost invariably better than high-end headphone amps, being over-engineered to drive harder loads.