Some of the premise isn't exactly spot on. There have been challenges in getting people to pay for music. There's a consumer trend towards cord cutting in television as a means of money saving.
Nevertheless, at this point, since the initial price point of using social media platforms has been free, there would be massive backlash if standard social media accounts began charging. LinkedIn charges for premium accounts, but the basic accounts are free.
The original premise of TV was free content that was supported by ads. Advertisers paid the network for the audience, and that still happens. With Facebook, Instagram, etc, advertisers now are just paying those companies for the audience. They will still want to see an ROI. Time will tell.