re: The advances are coming fast.
For sustained high power chemical still wins by a lot, but solid state power output is growing rapidly- and solid state is much more compact. I worked on a 1.5 kW Nd:YAG system made by TRW(at the time) that put out three 500W beams - The laser itself was an 8 foot cube, the control and power electronics would fill a walk in closet, and the cooling system would fit on a large flatbed truck. This was about 6 years ago.
It was originally designed in a project to make a pointing laser for the ABL... or so I was told.