I don't care about this dispute.

I don't know about your DIY experience, but the fellow I mentioned, for whom I built the deflection system for his laser soldering machine, also built a laser with which he cuts 5 cm thick deck steel. The other one who owns the laser engraver company built his CO2 laser in his basement. It quite easily cut into the concrete foundation of his basement. I doubt the power was limited to any small number of mW.

Since it's possible for someone to build a kW-size laser, I assume anyone determined to do so can, as well. The observation that I've made of my hand-held laser pointer projecting a spot on a wall 100 meters away suggests that a very-low-power laser source can do quite a bit, and from that I conclude that a rasterized display is inherently possible, perhaps with a bit more power than the 5 small 3V lithium batteries in my pointer will produce, but certainly not requiring kW.

Since the error in a 2-axis positioning system is a function of the product of the precision of the two axes, it seems obvious that one, rather than two, of these mechanisms would be more precise. When one of the mirrors doesn't move, but only rotates on a fixed axis, on which it's easy to hold tight tolerance, it seems pretty clear. It's certainly easier to construct a system with only one degree of freedom, rather than two.

BTW, If you think that text display is so trivial, try that with your stroked method. I doubt you'll find it easy. Keep in mind, too, that anything that can be done with text can be done with bitmapped graphics as well.

RE