Could Ireland remain a tech powerhouse without the multinationals

Given the multi-billion investments in plant and machinery and the skilled workforce in tech like pharma, medical devices and chip fabrication, in a doomsday trade war with the US, could any withdrawal by a US manufacturer be quickly replaced either with another multinational or by continuing to manufacture for the EU and others?

In a doomsday scenario all the international rules, including IP rights, would be dead or at least suspended. Could Irish plant just carry on? I know some pharmaceutical plants have changed hands and moved from making cutting edge drugs to generics, so what would stop the entire manufacturing base (and whatever r&d goes on here) from continuing if there was a market from countries also involved in a us trade war?

Software/services might be more mobile as the only infrastructure they need might be office space and good Internet, but the same question applies.