Question: If the car's acceleration is higher when the wheel's angular acceleration is higher(tangential acceleration=alpha x radius). Why are higher gears not used to accomplish the acceleration of the car instead of lower gears?

Answer: 
### The Rotational Inertia of individual gears doesn't matter.

You are way overestimating the effect of rotating gears on overall acceleration. The mass of gears is inconsequential compared to the weight of the vehicle (and the rest of the rotating mass. So a larger diameter first gear does have a slightly larger rotational inertia. But gear ratios overpower this small effect and renders it inconsequential.

In the end, acceleration is related to both the rotational and non-rotational mass. The small change in rotational inertia between first and second physical gears is immaterial.
It is down to power against drag ie rolling & aerodynamic. After about 40mph, the aerodynamic drag is larger and increases with the square of the speed.

Basically the vehicle has to push more and more air out of the way the faster it goes. Once the power equals the sum of the drag, acceleration will be zero.

And it won't matter if you have 4, 14 or 40 gears or an automatic or cvt.