Not defending the interfaces here, they do suck, but the elderly definitely aren't the target market for vapes. It's not unsurprising that they're not designed with them in mind.
You are correct though, they're not the target market. I would like to see some of the more modern conveniences redesigned though. Perhaps I can win the lottery and start a business for that need. Kind of like the bras and shirts with magnetic clasps for people with limited mobility.
I've never vaped and I run into complex button schemes regularly.