While Foxconn has expressed somewhat of an interest in potentially moving a portion of its operations to the United States, other supply chain manufactures that Apple relies on are reportedly less interested in making the jump. According to a report from Chinese publication qq, manufacturers are turned off by higher labor and operating costs in the United States.

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According to the report, Lens Technology, a supplier of cover glass used in iPhones, has said that it will not establish production lines in the United States. Despite the fact that power and land costs are lower in the United States than China, the company cites labor supply as its primary motivation for not switching.

Lens Technology employs over 70,000 workers in China, all of whom are below the age of 45, while in the United States the majority of labor is over 45 users old.

Furthermore, another unnamed Apple supply chain maker in Shenzhen, China explained that there’s already a complete supply chain in China, thus allowing companies to respond and adapt to problems and changes quickly. For instance, molding metal components to order takes 10 days in China, but up to a month in the United States due to the lack of a supply cluster.

Apple has been under increased pressure recently to move its production to the United States. President-elect Donald Trump has stated in the past that he will “get Apple to build its computers and things” in the United States and has offered the company tax incentives to do so.

Tim Cook has discussed the possibility in the past, noting that in most cases, a move to the United States would be both expensive if not impossible due to the lack of labor in the United States.

“China put an enormous focus on manufacturing. The U.S., over time, began to stop having as many vocational kind of skills. I mean, you can take every tool and die maker in the United States and probably put them in a room that we’re currently sitting in. In China, you would have to have multiple football fields.”

Apple did, however, ask Foxconn and Pegatron to investigate the possibility of manufacturing the iPhone in the United States. Foxconn noted that such an expansion would be worth $7 billion and 50,000 jobs, while Pegatron said the cost would be too big of a burden.