Your calculations imply that absolute thrust and efficiency are the most important aspects of spacecraft propulsion.
Obviously you're not looking at "all the facts" either, since by your logic that would make currently used ion thrusters quite useless. In contrast to the CSM engine, not only does an ion thruster provide mere fractions of a newton of force, if we could even push one to 91.2 kN, it would require Gigawatts of power. Yeah it's no "tera", but it's not the pinnacle of efficiency either.
Besides that, while I admit I don't fully understand how you got 27 terawatts, I do understand that this is not a physically unattainable number. In fact, a kilogram of matter has enough energy to sustain that output for many weeks.
I am obviously looking a bit ahead of what we can currently do by burning fossil fuels, but I am by no means looking into the realm of the impossible.