Taiwan supplements scarce Patriots with domestic missile work

Why is Taiwan's Patriot missile stockpile small relative to the threat it faces?

Available production limits the stockpile, while Taiwan has been developing more domestic missiles and maintaining defense-technology links with Israel.

Limited Patriot production constrains the stockpile available to Taiwan. Taiwan has also worked for years to produce more missiles domestically. Defense and technology links with Israel are identified as part of that development. Both countries are described as working on improvements to missile systems, including Patriot.