We know Fusion is Possible...We did it already long ago... The Hydrogen Bomb. The question is, can we do it in a controlled way and harness the energy effectively? China had a fusion reactor running for over a minute already.
But until we also invent "replicators" that convert energy into anything we want (matter).... Oil will still be needed to make all the things that are made from oil, which I understand is a lot of stuff.
Beam me up Scottie.
All just my opinion/view/thinking.