In this argument, the manager recommends that car dealer should change the focus of their business from selling cars to leasing them. To support this recommendation, the manager points out that leasing new cars has surpassed the number buying new cars. Then, reasons that the majority of drivers will be driving leased this year. The argument relies on a series of unsubstantiated assumptions, which render it unconvincing as it stands.
In the first place, the manager unfairly assumes that when comes to the case that the cars reaching their driving age this year, most car owners would choose to lease a new car but not buying a new one. Then as a result majority of drivers will be driving leased cars this year. It is true that people inclined to lease in the last five years. However, this would not indicate that this year most people would also choose to lease. It is entirely possible that before this year many people do not have enough money to buy a new car, so as an alternative they choose to lease. But five years past, the situation change they could afford a new car. The manager's assumption also ignores the possibility that people's consumption conception suddenly changed this year, they all come to purchase new cars. Then new car consumption this year may outnumber car leases. Without taking into account these possibilities, the manager cannot persuade me that majority of drivers will drive leased cars.
In the second place, even if this year most drivers would chose to lease, changing the focus of the car dealer’s business from selling cars to leasing them would get profit is uncertain. Car dealer could not gain the same profit from leasing a car as selling out a new car. Then the mere fact that the number of people leasing new cars surpassed the number buying new cars could not ensure more profit. The manager also fails to take into account other factors that would influence company's profit. Convert business direction may result in inefficient customer loyalty, short of experience, market saturation and competition. In short, without any evidence that the car dealer would handle all this uncertainties successfully, the manager's conclusion remains dubious at best.
In conclusion, the argument is indefensible as it stands. To strength the argument, the manager must rule out the actual circumstance of leasing car market this year. To better access the argument it would be useful to know other factors that have influence on company's profit.