They had the ability to record video at home LONG before 1981. People had handheld "Super 8" film cameras ages before this, which they used to film their own home movies. Of course, this is a little different from videocassettes, just like LPs are different from audio cassettes, but it didn't take a genius to see that home video was going to move to videocassettes before long, they just needed cameras that could record directly to them instead of to film.