Upgrading Ellis Island is more cost effective in any long run scenario for those seeking asylum. No need for fences over there.
Except that you overlook the facts that:
While you are upgrading Ellis Island....
Approx 1500 unidentified illegals (potential threats to this country and out citizens) have been / will continue to enter the US illegally PER DAY
--- EVEN AFTER Ellis Island has been upgraded, with no border wall / nothing to stop them, at LEAST 1500 illegals will continue to cross illegally into the US
(How are you going to transport the THOUSANDS of illegals waiting just inside Mexico to enter the US to Ellis Island?

)
This weekend's violent attempt by illegals to storm the border and push past ICE / BPAs / DHS shows the illegals have no interest in entering the US through officially designated Ports of Entry...THAT ALREADY EXIST