Good comment from Yukito Atari on youtube :

"You cannot compare analogue wireless signal from the 70'S to the modern digital wireless signal from 2017. It's like comparing a lemon to a pineapple. In the 70'S, the signal was requiring strong output because all the other device was making interference and since the signal was analogue, there was no way to compare if the data was corrupted or not, in recent year, a CRT TV was killing the whole Cellular network from a neighborhood and it finished with the provider buying a new lcd to that broken old fart. Nowadays, there's no more CRT, less analogue signal and the device nowadays use checksum to verify if the transmission got corrupted and reask the source to resend the data, they use a more specific range of signal and not broadcasting the signal on a large range of spectrum so they are not interfering and since they all got mac address, they know which device's who. Remember in the 90'S when you where using a cellphone in your car and in the middle of a conversation, you got some new uninvited guest into the conversation because of the interferance, it's not happening anymore. You need way less power to transmit data to specific mac address into a specific range than broadcasting on every range and channel the analogue signal hoping the other end reach the transmission because it has no specific address. I have done some class into cisco networking back in 2012. If you got the money or find a way to get the online class for free, give it a try."