Election day is set by the states, the date the electoral college meets is set by Congress, and Congress can override the states as to the date of elections for federal office, thus a single election day since the mid 19th century. Congress could change the election date but the terms of elected Federal officials end, per the Constitution, at the end of their term. So though you could put off the election I suppose, you’d have no one running the Executive Branch and Congress as their terms expire so the Constitution would then be in the trash.
Somehow, I don’t think either party dares put the US Constitution in the trash yet, but I’ve been wrong before.