You could argue he's just trying to give an excuse for delays in production, but I think its plausible to believe he's doing it for his reason given. It also looks great on Tesla, shows that they think about the customers which further increases sales.
I think it's probably a bit of both. Sure, he could produce a few Cybertrucks now but the risk far outweighs any potential reward, to which I would argue there is none in shipping a few units now. So obviously he's going to wait until they can get production going at full scale before doing anything. The benefit of that is he is able to take the moral high road and give himself a pat on the back while making it seem like preorders are getting a million dollar vehicle for $40K. Wins all around.