Aeronautical engineer here:
The real reason why airplanes don’t go backwards using reverse thrust is not noise, it is the risk of an engine surge.
Reverse thrust is only used during landing while the airplane is still going forward at a certain speed (notice that the reverse thrust is shut way before the airplane is at rest, during landing). The risk is that the engine sucks back up its exhaust gases + the fact that reverse thrust increase considerably the air flow pressure in the rear side of the engine. At low speed, if this pressure gets too high, the air struggle to moves backwards in the engine and the air flow can stall in the compressor leading to a [compressor surge](https://en.m.wikipedia.org/wiki/Compressor_stall) which is very damaging.
Major airline pilot here. We don’t have backup cameras or mirrors, which in a safety-minded industry introduces a lot of potential risks if we were asked to just backup on our own. We also can’t see much of the plane from the cockpit… All the pointy sticking-out bits are behind us. Plus, there’s a lot of coordination that goes into backing off the gate that’s best conducted with a team. Wing walkers are great for alerting other vehicles to our movement, helping to avoid hitting ground equipment or fixed obstructions, and directing us to our specific spots on the ramp before being released for movement under our own power. Even if I had motors in my wheels, I wouldn’t want to move a machine over 100ft long in every dimension without someone making sure I wasn’t going to break it.
Planes reverse by redirecting the air out of the back of the engine forwards — called a powerback. While most aircraft can do powerbacks, it is usually not allowed by company procedure since it blows debris on the ground up into the engines. Planes with tail mounted engines were more likely to powerback than planes with low wing mounted engines.
https://en.wikipedia.org/wiki/Powerback
The wheels on planes aren’t motorized, the only propulsion the aircraft has are the engines.
Thrust reversers dont push air straight back, instead they push a lot of air out to the sides. Because engines are close to the ground, this can create a lot of noise, become hazardous to anyone standing somewhat close by, and can potentially knock up debris from the ground and potentially lead to that debris entering the engine
It also burns fuel, which airlines don’t like wasting unless it’s necessary.
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