I personally don't assume anything - it truly depends on the person. I'm 48 years old, majored in computer science in college in the late 80's, and I've always worked in technology, and been personally interested in technology, but I know many my age who can barely use a smartphone or work a smart TV.
My dad is 77, and it's a real struggle with him...he's not learned or "kept up" with technology at all over the years, so many things that are just intuitive to many of us who are tech savvy are completely beyond his imagination, since he has no frame of reference. Swiping the screen left or right or using other gestures is just not something that would ever occur to him to try, so learning to use his iPhone has been really slow.
I'm guessing that if the OP's parents were tech savvy, he wouldn't be here asking this question, because they'd be picking their own phones based on their personal preferences...so we're assuming they are not tech savvy in this case.