Technology is very important in determining the size and scope of an industry. Home countries oppose export of technology because this would provide their trade secrets to other countries.
Technology defines the quality of a product manufactured. Exporting the technology used in home country is not viable because this way the countries lose their comparative advantage to other firms. When other countries would have the same technology they would be able to make the same products. This way there would be less and less demand of products made by home country because it would be readily available in the market.That is why technology is considered as the barrier to entry in an industry.
The international market is very demanding and complex. It is not very easy to understand its mechanism. Product decisions are made considering various different things such as technology, level of similar products internationally, product quality, international standards compliance etc.