Pop-culturally speaking, 1999 seems like yesterday to me. I'm not so certain there's been some fundamental sea-change in how the deaths of actors are dealt with in that time. I think De Kelley's death may have been treated much the same today, or Ann B. Davis's much the same then.
Except it was barely mentioned in 1999.
Either something changed or he simply was not thought to be worthy.
I think he was worthy--so I do think have changed.