There are many younger players capable of winning tournaments (and deliver entertaining match-viewing), but none seem destined to be the kind of dominant player that Tiger had been.
Players who can dominate a game like Tiger don't come along very often. At one point, watching their game is electrifying because we want (or expect) to see Great Things every time they play. Just how far into the company of all-time greats will they penetrate? In Tiger's case, I watch because I still hope to see him back on his form of old - adding a few more accomplishments to his legend. Watching today's younger players doesn't deliver that particular emotional payoff.
To me, golf without Tiger is just not quite as compelling. I suspect it'll be the same for tennis without Serena Williams, Roger Federer, Rafa Nadal, or Novak Djokovic. When I was young, it was all about Arnold Palmer, Jack Nicklaus, Margaret Court, Billie Jean King, Rod Laver, Ken Rosewall, and the like. They mark eras that are still remembered, despite all the great players that have come since. The recent era, which will be closing in a few years, seems likely to be another like it. Only time will tell.