The assumption that you keep making which is wrong is that pressure in the engine pushes against the outside pressure (atmosphere) to produce thrust, it doesn't. The outside pressure actually works against the thrust of the engine by slowing down the escaping gases. A good way to get your head around this is to think about what would happen if you stopped the gases from escaping the engine by blocking off the exhaust† exit. If you did this the pressure would be equalized in all directions and no propulsion could occur.
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The outside pressure you say "works against the thrust of the engine by slowing down the escaping gases" creates what's called "compression". Do you know anything at all about engines? How about the wrench and the screwdriver?
It's funny that you mention compression, as it's the compression of the gases released from the burning mixture that push in all directions causing the pressure within the engine and thus the thrust. While a small amount of compression would occur between the escaping gases and the atmosphere there is nothing restricting the flow of gases outside the rocket so it's negligible.
I've fixed a number of four stroke engines over the years, so I'm quite familiar with the internal combustion engine, wrenches and screwdrivers. How about you?
The atmosphere is under tremendous pressure and greatly restricts the flow of expanding gasses from the rocket nozzle. The pressure caused by the flow of expanding gasses compresses the atmosphere and it's this force between the rocket engine and atmosphere that causes thrust.
At sea-level atmospheric pressure is a mere 14.7 psi - not really the definition of "tremendous pressure" is it. Nor does the atmosphere greatly restrict the flow of expanding gases, just take a look at exhaust systems in cars and see how well a naturally aspirated engine runs without an exhaust.
If 14.7 psi isn't tremendous pressure then perhaps you'd like to explain why when BADecker sticks his head in a vacuum chamber at 0 psi it explodes with considerable force? As for the atmosphere not reacting to the expanding gasses exiting the rocket nozzle, I'm sorry but you're either a fool or a shill to state this.