Computer and TV (while the largest slice) are holding steady, Smartphone is the one ballooning.
But these are _mostly_ people at home, not in the job market so what should they do instead, volunteer, read? I dunno if I would castigate them for this.
To me, looking at the charts, the TV line seems flat for seniors but the smartphone line is a major increase since 2015. My interpretation is that seniors have added 2+ hours per day of screentime in the last 4 years and 100% of the addition is smartphones.
Edit: Also, anecdotally, TV is a quite a novelty for me. I had basic TV ears when I was a kid, but never cable. I was ~31 before I got cable TV (always was affordable but never a desire). I definitely personally see TV as more of a novelty than smartphones.
Edit: Also worth noting that the article is about media consumption but the headline (and subheader) only references "screen time". Could be confusing if comparing to groups outside seniors, who use screens for a lot more than media consumption.
