What happened after 885 is the reason the work survived at all. The expelled disciples, among them Clement and Naum, went south into Bulgaria, where Prince Boris received them. There the Slavonic books were copied, schools were established at Preslav and at Ohrid, and the literature grew instead of stopping. Moravia itself reverted to a Latin church within a generation.
It is also where the alphabet changed. The script the brothers made was Glagolitic. The Cyrillic alphabet was developed in Bulgaria in the decades after 885, joining Greek uncial letters to signs for the Slavic sounds Greek had no letters for, several of those signs taken from Glagolitic. It is named for Cyril and he did not devise it, which makes the name a record of where the tradition begins rather than of who drew the letters.
Glagolitic did not simply vanish. It held on longest on the Adriatic coast, where an angular Croatian form stayed in liturgical use for centuries after it had gone everywhere else. Cyrillic travelled with Orthodox Christianity into Serbia, into the Rus and beyond, and its descendants are the everyday scripts of a great many languages now. Both brothers are venerated as saints in the Orthodox and Catholic churches and are named apostles of the Slavs.