This is just not true. Norway quaranteed people coming from infected areas, and brought up understandable restrictions by a unified front across ministries, sparrowheaded by the Prime Minister. Curve of infected and deaths seem almost linear, and the Gov is considering opening up low-hanging restrictions after Easter.
The clue was right responses at right time, correct nation-wide communication, coordination and leadership. With earlier response, maybe this could've been stopped at borders. But effectiveness is doubtful, since most countries have dismantled pandemic and crisis capabilities.