Recorded sound made music available to the average citizen. So there is a difference.
I'd disagree with that statement to the extent that music has always been available to the average citizen. Mozart wrote many of his operas for the common folk - operas were the mass entertainment of the day back then. The only catch is that you had to go to the theater to see the performance. Church music for centuries was a way of communicating the liturgy to the common folk in an enjoyable way. People have gone to dances and concerts for probably as long as man has made music. People even learned to play musical instruments for their own enjoyment.

The advent of recorded music didn't expose people to music for the first time, it simply made it available in the home. People could listen at their convenience even if they didn't play. Prior to that even rich people had to have live musicians if they wanted music.

One catch is that as something becomes more commonplace, we tend to take things for granted. Many people probably don't appreciate music as much as they might have in the old days, but that is also true for things like cars, TVs and telephones. Welcome to the modern world and just think what its going to be like as we continue down the road of increasing technology.

That said, Ella Fitzgerald and her kin will no more be "forgotten" than Mozart or Bach have been forgotten. Sure, they are not going to get a lot of air time on the radio or TV, and their million seller days are long gone, but that is life. The people who care about that music have it available. Young people here and there will continue to discover the magic that music has to offer, but it is likely not to be on the same widespread level as during their heyday. (Even then there are exceptions. Tony Bennett experienced a resurgence of popularity with the young crowd a few years back.)