I guess after Bitcoin reached its first ATH in 2017, some mainstream Media started referring to ALTs like XRP and ETH by the abbreviation of crypto. I started hearing crypto from that time, though I may be wrong this is my opinion.
Right, I agree with you. Back in the year, 2017 when bitcoin reached 20k$, that's when the time the word crypto abbreviation became popular. And I guess people tend to create a shortened form of the word because it's much easier to read and write.