You need to share when you encounter something worthy of. Media apps didn’t allow sharing, or they presume closed ecosystem. That’s why tablet versions where doomed from the beginning (remember Murdoch’s «iPad-only» The Daily).
It is publishers, who need fully controllable vehicle, not the audience. Media themselves don’t need better vehicle as well — they already have a good one. But more important, media need the ecosystem with freely circulated content, which is detached from its source of origination. That is what kills old media orgs.
The web buys people by its openness. Separate apps, closed platforms, or any attempts to close content — just contradict the very essence of the web.