The same argument could be made for the even teenier and tinier wireless earbuds (which e.g. in case of the Bragi earphones hold two noisy radios in each earpiece). Besides, you don't easily "crack a shield" in a phone.
They already are. If you are not happy with the builtin DAC/amp, you can already use external ones.
If you are talking about earbuds (as opposed to fullsize headphones), keep in mind that all the components (i.e. batteries, drivers and electronics) now have to be squeezed into a similarly tiny volume that only the drivers occupy in wired earbuds. There will be compromises. And one fundamental issue with wireless earphones won't go away: The need for extreme power efficiency. Hours of runtime from a battery the size of a pea will always require compromises in the forseeable future, be it limited power output of the amp in the earbud or audio compression to reduce wireless bandwidth.
BTW, the relalatively low-impedance audio signal on a headphone jack is not very susceptible to cable noise. In any normal environment a 3ft cable will not cause audible degradation as long as the cable isn't damaged.
Someone who gets it
