How is that different from the thousands of different languages that did not have alphabet until recently but then got one created by linguists or missionaries (or often someone who is a little bit of both[1])?
Cyril and Methodius (who created the Glagolithic Alphabet, not the Cyrillic alphabet) weren't even the first Chritian missionaries who created a new alphabet for a language that didn't have on in order to spread Christianity. I believe the first one was Armenian (in the early 5th century).