They may have trusted family members, friends, or neighbors who they feel comfortable allowing the management of their internet connected devices.
Apart from printers and smart TVs, less than half of US households have any of those other devices.
https://www.statista.com/statistics/1124290/smart-home-devic...
Anecdotally, most people I know who own those devices are the more technically inclined. Especially the thermostats and light bulbs. Even the doorbell surveillance networks have low penetration.