The purpose of the Friday Khutba is listen to that particular Khatib of that Masjid which you are physically attending. That is why it is 'Sunnat' to face that Khatib of that Masjid which you are attending who is in front of you and to give the Khutbah and to listen to it is also Waajib for those in attendance. See 'Mirqaat' commentary of 'Nurul Ezza' and 'Baidai Sanai'. Thus the question before Zawwal for the far-away listener will not apply nor the necessity to listen for the non- attending one.
What will the listener do if conservetively the Khutbas of Makkah, Madinah , Al - Aqsa, Deoband, Al- Azhar are relayed via mordern transmission ? Must one listen attentively as in jurisprudic 'Waajib'? This is not logically possible or practical.