OLE is going to start becoming big in decks, or maybe skip it completely and go to HUD's. No more motorized TFT screens.
As for amps, I suspect efficiency will go up, size will go down, "smart" amps will be developed with more sophisticated micro processors in them.
Power transmission may go wireless (Tesla, back in 1891 for goodness sakes came up with that idea), or possibly someone will come up with a replacement for speaker wire that is not cost prohibitive to manufacture.
It's harder to envision what speakers may be like. We've already had many new designs in the last 50 years (Planar) but I think a radical change in thinking is needed. We seem to be stuck on "moving air" with some form of cone, square, etc. Maybe we could come up with something that uses the surrounding air as the "cone", we could give it positive / negative charges or something like that to create sound.
I aint gonna be around to see it, but thats life