Heh.
You ninja'd me in the 5 mins it took me to run a test.
Scorched earth has the same effect as a nuke, except it does not destroy ships of any sort, both friendly and hostile ships survive the destruction of the scorched earth command station.
The destroyed systems have no supply, which means even an econ command station built in the system provides no resources.
Which means for the entire game (assuming single homeworld start), you have:
12 resource collectors in your home system.
13,000 knowledge.
A single system for energy reactors. A mobile builder requires supply, so no building reactors outside your home system. The efficiency penalties will quickly cripple your fleet.
Engineers do not require supply, so you could at least repair your fleet.
Assuming 205 metal and crystal and the most efficient building of reactors, 10 Mk I, 7 Mk II, 2 MK III, you get a total energy production of 260,536 energy. That is absolutely crippling.
In my test game I have 263 metal/s and 191 crystal/sec so to even maintain that I'd have to use the crystal manufactory.
After the metal hit for the manufactories, I'd have 34 metal/s and 2 crystal/s to build ships with.
Assuming you don't spend knowledge on economic stuff, with only 13000 knowledge the entire game, that would be a tough call.
So yes, I'm calling 2 scorched earth AI's impossible on a single planet start.
Now a multi-planet start on the other hand.....
D.