Earlier quoted context omitted.
How old are you, and what part of Mexico are you from? I really think it was in the early 1980s when the SEP started to spread the holiday. It's kind of hard to figure out.
I am 55 and we did celebrate Día de Muertos back in the 60's. Then we would bring flowers for our deceased, and outside (and inside) the cemetery it would be a lively scene with basically the whole town there doing the same, vendors of flor cempasúchil, sugar skulls, little calaveras (skeletons), etc. it's been an event my whole life, and something my parents celebrated, it's not new.
I have to mention that it precedes "Día de todos los santos" so it's (or was) a two-day celebration. First remember the dead, then celebrate they've gone to heaven.