The main problem is that -- especially with laser fusion-- you are not inputting 1 unit of electricity and getting out 1.2 units of high grade heat. You are inputting 100 units of electricity, most of which is lost as low grade heat through wires, cooling devices, etc to power a laser that outputs 1 unit of photons. The fusion adds a bit of energy, but not enough to surpass the 100 units you put in. I don't know the exact efficiency of these lasers, so 100x may be wrong, but I think I'm in the right order of magnitude.