i would like to add more.
1) Its not confirmed but heard that in Japan if a car manufacturer manufactures car above a certain no. then it will have to pay a lot of tax to the government according to laws made for regulating the industry. these laws prevent monopolies from developing in the market and also protects the businesses of smaller automobile manufacturers. For example if a Suzuki develops a car that captures a major chunk of the market then it can put many automobile makers out of business.
Now imagine such laws implemented in Pakistan: Corrolla coming with different name with the badge of Suzuki. Suzuki will have a hard time maintaining quality to compete with Toyota. Toyota will be indirectly benefiting from the Sales of Suzuki. If Dewan motors purchase the same design when these two manufacturers have manufactured the car upto the limit where minimum tax is applicable then they would also come in business.
Similarly Mehran manufactured under a different name by Honda Atlas motors will be selling like hot cakes with the better quality standards of Honda. The Suzuki will have a hard time selling their own product in the market. Or maybe Mehran would be produced by Nissan Gandhara.
2) Plants in Japan manufacture thousands of vehicles per day and may still have their production capacities limited. If a company sells a successful design to another manufacturer then they can benefit from their surplus production capacity.
Now just think what d.ou.che bags are our policy makers when so much can be done...