I can plug a set of $100 headphones into a motherboard with a cheap audio chip and it'll still sound far better than than a Turtle Beach setup or a set of ear buds plugged into your TV.
The option is there, it's just not good enough for you. The only thing you're limited by is your budget. If you're spending top dollar for premium headphones, you should spend top dollar for premium equipment to drive them.
Again, the hardware I'm talking of (a pair of 3.5mm I/O's with an audio chip) is dirt cheap and worlds better than current licensed aftermarket headsets.
By your logic, should Microsoft and Sony also include an amplifier along with speaker outputs for 7.1 surround sound? I know a lot of people that want surround sound without having to buy a dedicated receiver that cost 10x as much. Why can't they just plug their speakers into their consoles, without having to buy a receiver? The television speakers aren't good enough!
Thats a nice way to ignore the 1000 shades of grey area in between high end sound systems and proprietary limitations. You're not making any points with circular logic. I don't need to buy a large expensive home theater system for quality sound, nor should I be limited to a narrow range of sub-par Astro's because Sony and MS dont want to include simple standard hardware. You still fail to explain why Sony or MS can't simply solder a $10 amplified audio chip with Dolby Headphone to the PS4 or Xbox One mobos.