Here's your current snapshot:
Natural Gas: 32%
Coal: 30%
Nuclear: 20%
Renewables: 17%
Other = rest
I think what's next is the bigger challenge we have with wind and solar and that's energy storage. Generally speaking, when renewable energy is produced, it needs to be fed into the grid and used. And that's a problem if the wind only blows at night like it does in, say, Texas. So I think a battery storage for renewable energy is a problem to solve first (and it's getting there) and then we can address replacing coal. But we're a long way a way from this happening. Like it or not, the coal lobby isn't going to just lie down and surrender. People depend on these jobs in Appalachia, even if the jobs are killing them (and they are, you should watch Frontline/NPR's piece on what coal mining has done to generations of workers).
And, you're right, it's not cheaper. Not now. So asking people to voluntarily switch their energy consumption to renewables if given the option better damn well come with a better carrot than 'you're saving the planet'. I want to save the planet, but I also want to feed my family. I'm just being honest. Fortunately, my energy comes from Hydro, so I'm detached from fossil fuels already.
We should have explored nuclear more as a viable option in this country. The last nuclear power plant built here was, what, the late 70s? Safety standards and technology has come a LONG LONG way since then. Think of what we've done with cars since the 70s. We can build safer, more efficient nuclear; we just don't want to do it. You know who does? China. They take the task of cleaning their air up seriously and so they continue to build nuclear using the latest/greatest safety and technology available.
What I see going forward is solar roof tiles/shingles on homes with a battery wall attached to the house. Homes powering themselves and attached to a grid only if need be. I think that's probably what my kids will have when they become homeowners.