In 'the future' there won't be as many big newspapers businesses. That seems obvious. They're already closing down. The ad revenue isn't there to support all the newspapers we have. There are rival information sources. But there will still be lots of newspapers. That doesn't mean all newspapers will disappear. There's probably enough ad money for some to survive, maybe less money than now but still be lots of money. And newspapers will be funded in other ways; local authorities, community groups, charities, whatever. The newspaper form factor is too good to just disappear because some businesses are failing. There will be lots of newspaper businesses.
There won't be as many big TV businesses. As above. Ad revenue declining, lots of competition, harder to make money. But there will still be lots of TV. As above. There'll still be enough ad revenue to support lots of programmes, though they may not be organised and distributed exactly as they are now. Other funding models will arrive. If you want to be in television you'll still be able to. You just might get paid a bit less, have to be a bit better at your job and might end up a bit less famous.
There won't be as many big movie/advertising/publishing/music etc businesses. I guess you can see where I'm going here. But there will still be lots of movies/advertising/books/music etc. And I don't just mean that they'll all become cottage industries. Big, global, megacorps will survive. There just won't be quite as many, and they won't be quite as powerful. (Though I guess some might be more powerful because they'll have a bigger share of a smaller market.) So if you really want to be a music industry mogul you probably could be. It's just going to be harder. The marketing world will still want big agency networks, just not as many, and doing slightly different things. There'll still be publishing companies publishing books. Will they have the same cutlural dominance as in the 20th century? Possibly not, but neither will they have none.
All this is, of course, obvious. But I get fed up sometimes with people going on about the death of some industry or other. (Though, thinking about it, I suspect I might have done it myself) The issue they're all facing isn't death, it's decline in the size of the businesses involved, but that's often coupled with a growth in other things. TV's business troubles have led to a creative rennaisance. Newspapers are more widely read than ever, and probably more influential, while struggling to make as much money as they used to.
If you really want to debate the future of these things the thing to discuss is how significant that decline will be. Will Industry A shrink to the size of, say, Radio (which is still a massive and fascinating business) or to the size of Music On Vinyl (which isn't a massive business, but still represents a living for many people.)