The Americans do not give up technology that's on their export control list.
The Europeans and Israelis are much more lax.
The Koreans, Japanese, Turks etc do not have any technology that's on the American export control list.
By Oh Seok-min SEOUL, May 22 (Yonhap) -- The arms procurement agency said Wednesday it w...
en.yna.co.kr
The contract to buy 40 F-35 Lightning II fighters was concluded in an "offset" manner that called for the American defense giant to transfer dozens of key technologies to South Korea in exchange for purchasing the expensive fighter jets.
But implementation of the deal did not go well as the U.S. government refused in 2015 to issue an export license for four combat jet technologies, including a key radar technology, to South Korea, though the U.S. firm agreed to provide 25 kinds of technologies under the offset deal.
South Korea’s DAPA has purportedly initiated the procurement process for 20 more F-35As.
thediplomat.com
However, the United States refused to share four (active electronically scanned radar, the infrared search-and-rescue systems, the electro-optical targeting pod and the radio frequency jammer) out of the 25 technologies.
So they are willing to transfer a lot of technology, stuff that we already have, but not the key ones, stuff that we do not have. Otoh, we have had multiple radars, IR sensors and EW suite deals with the Israelis, alongside other electronics, and a series of upcoming engine deals with the British, Russians and French.
Contrary to what you stated, the Koreans had to make their own radar, just like our Uttam. This is from day before.
South Korea has unveiled an indigenous active electronically scanned-array (AESA) radar prototype for use by the Republic of Korea Air Force’s (RoKAF’s) next-generation...
www.janes.com
The Japanese and Turks are also going for American-free jets. Both have developed their own indigenous technologies. The Japanese have gone one step further with their own engine tech as well.