There is really no such thing as a "digital" antenna - the same old antennas of yesteryear will pick up broadcast signals - and of course these channels are still very much "broadcasting" - not sure why he would claim broadcast television was "replaced" - the signal type was changed from analog to digital, but not the concept of broadcast television stations. Some newer antennas come with newer technology to amplify signals to make channels more stable because with digital broadcasts either you have the station, or you don't, but the signals are still picked up in the same way on VHF and UHF bands. A lot of antennas on the market make a lot of bogus promises and may pick up next to nothing - you really have research to make sure it is a quality product.
Unfortunately, with antenna programming you still suffer through the commercials. Cable/Satellite solved that problem with DVR capabilities. I searched streaming services that would allow me to record and fast forward through commercials after I canceled DirecTV. Now I get the same programs (less the garbage channels) with streaming for half the cost of DirecTV. Happy Camper!
My brother bought a HD Antenna a couple of years ago. Brings in all the HD channels that are ‘behind’ the traditional network channels. Simple air antenna...no monthly fees for anything. Plenty of channels for free.