In twenty years there will be fewer cars in use than there are today

I do not agree with the point of that in twenty years there will be fewer cars in use than there are today. My reasons are as listed below. ( <---- I would leave this sentence out, it sounds like filler)
My main reason is that with our econiomic growing economy, there will be more and more people [who can afford cars] learning to drive, and that may lead to a growing number if car demands more demand in the future. People need cars to go places out instead of going out on by foot for the sake of driving by oneself is a more flexible way of transportation. Going out by bike or on foot is a convenient and more green way, but when it comes to limitations like distance and energy there are clearly disadvantages. For example, after a long day of working at the office, few people would like to bicycle back home.
In addition, with the developement of the modern industry, intense competition between car makers means either exclusive limosines (this is a terrible example, only the absurdly rich take limos on a regular basis, most people are lucky if they get to ride in one for an extremely special occasion like prom) or cheap second-hand cars will be better than they are now, all while the price reduces. This would be a factor one may own more cars at hand.
Furthermore, twenty years is not that long a time that could change a lot. New transportion vehiles needs time from invention to upgrade, take the cars for instance, first come horses, then comes carriage, then the Revolution of Industry Industrial Revolution. Fewer cars in use means another form of transporation may appear, there may be another transportation mean appear but the fact is that twenty years is too short a time to deliver much.
In conclusion, bees congregate live in hives, some fish move in schools, ants gather in mounds, wolves live in packs, deer associate live in herds... people get around by car. It was not won't be until a new form of transportation that fewer people will drive cars means substitute cars could we find few people use cars, and apparently, and twenty years is far more a matter of an exaggeration than a plain goal.