The problem is, it's not showing a reality and cannot show a reality.
No, it does show a key part of reality.
Yes, there is almost always some external force, but that doesn't change the fact of what happens without it, and the impact of the force.
An object in motion will stay in motion unless acted upon by an external force.
It clearly will not stay in motion then, because there's always an external force acting upon the object.
No, it is actually that it continues with its motion. An external force will change the motion, which can be to stop it (in some reference frame) or it could be to speed it up, or just change the direction.
The only way you can argue this is to use the fiction of a vacuum of so called space to say something will move forever once in motion or stay perfectly still forever if left in space.
Or, as was originally done, we can look how the different forces impact motion, and extrapolate back to no force.
We can see how applying a force in the direction opposite motion slows it down. We can see how applying it for a longer amount of time or a larger force will slow it down more.
You can also apply a force to negate an external force to see what happens when the net force is 0.
So no, it very much describes reality.
But lets consider what if this law was fiction.
Well that would mean objects at rest could magically spring into motion with no application of force, and objects could just magically stop for no reason.
It would mean rockets could be fine in space, as without the first law there is no requirement for a force for them to move.
No. That sudden lurch forwards is the atmospheric slosh effect.
While pure nonsense, that just pushes the problem back. Why does the atmosphere slosh?
Is it because it is an object in motion and will continue that motion?
Sure sounds like you are just using it for the atmosphere so you can pretend it doesn't work for other objects.
But we can see what effect that has by looking at a helium balloon.
The atmosphere sloshing forwards causes the balloon to be pushed backwards.
But the best way to show it is nonsense is to not be in a car. Instead be on a bike. The same thing happens.
In fact, if you do it bad enough, you go flying off the bike due to your momentum.
But of course, all of this is just another pathetic distraction from your complete inability to address the issues which clearly show your claims to be nonsense, which clearly show rockets MUST work in a vacuum.
Again, TELL US HOW THE GAS ACCELERATES!
What is it pushing on (noting that means it is pushing that object)?
Again, the only thing which it can push on is the rocket. Everything else is on the wrong side.
Likewise, tell us how the rocket accelerates.
What is pushing on it? We know it can't be the atmosphere as it is on the wrong side or the rocket is protected from it by the gas coming out of the rocket engine. The only option is the gas.
But if the rocket is pushing the gas out of the rocket and the gas pushes the rocket, that means that there is no need for the atmosphere and the rocket will work in a vacuum.