Also had another thought on that pesky air in the way. Something related to your point is called Max q and occurs very high up still in the atmosphere, even above most of the air, because of the speed also involved. The advantage of a rocket is that they can manage the ratio by backing off the throttle until getting past that point. But important to this conversation is how high that occurs. Even if the mass driving avoids the lower air, it still has to come out of the tube at a comparable speed to attain orbit, so it will run into its own Max q type effects as it exits, and then even further up. The stress on a vehicle would certainly be far greater than "just" a rocket launch.