TOEFL: Car usage in 20 years later

I am preparing for my TOEFL that I need some corrections on it. Could you please rate it in a scale of 5. Thanks.

The issue of how many cars will be in use has been a controversy for many people. Since people do act by making a prediction for the future, one prediction one has to make about the future is whether many cars will be in traffic or they will be deposited in the trash. Although it is mostly true that a great number of people think cars will be replaced by another kind of new portable devices, I believe that more cars will be on the road in 20 years' time than that is in today. We may see this statement is being true from a couple of examples from observation and knowledge.

First of all, two decades are not considered much time for the breakthrough of new technology to be invented and rise in the markets. Devising a new technology and persuading public to use it wisely and in many numbers will take more than 20 years to accomplish. To make clear example, let's simply think about 20 years past from today. It was 1995 when the only rich people with high prestige used to drive vintage automobiles made by USSR in my country. My grandparents once told me that only one or two cars had been in the downtown road of the capital city. In my opinion, automobile usage and development are just beginning to spread to the all parts of the world.

Finally, instead of perishing from the earth, cars would develop into more environmental and powerful mean of transportation. Because many scientists are devising more gas-efficient and more comfortable ride as possible, people in the future are going to accelerate their wheels with such ease and even with a few bucks in their pockets.

As a result of close analysis of cars' usage in today and that in the 20 years later, we may conclude that immeasurable number of cars would be on the road and manufactories making automobiles will open their new branches in every countries in the world.

Hello.
Your writing doesn't convey enough information about the topic.
You wrote "first of all" at the beginning of the first paragraph And you began the following paragraph with finally! It was better that you wrote another reason for your writing as the second reason then used "finally" as the third part of your writing.

Good luck.