More than a couple centuries - but dead isn’t quite right. While it wasn’t spoken in most Jewish enclaves, it was still used in all religion and quite a lot of commerce and literature. Most practicing Jews knew Hebrew, even if they did not use it in daily life. Jews from different countries often used Hebrew to communicate - mostly in writing because it was the common language they would both know.
Books have been published in Hebrew more or less continuously, including the first printing press in in the Middle East (now in what is Israel) in 1577 printed books in Hebrew.
Hebrew has never been dead - it just wasn’t used because most Jews lived in countries that spoke other languages that Jews learned and often created pidgin dialects like Yiddish (and others).
It is not like a bunch of zionists taught all the worlds’ Jews Hebrew, but if you put a German Jew and a Russian Jew in the same room, the only language they would both know is Hebrew.
The difference between Hebrew and Latin was that only the Catholic clergy and intellectuals wrote in Latin.
The average Jewish kid could read and write in hebrew. Even if it wasn’t spoken.
Even in Morocco, the dialects spoken were often written with Hebrew characters - including a dialect of Arabic written with Hebrew characters.
They also would have more than a passing knowledge of Hebrew, obviously.