Having used Kodi for close to 15 years (from XBMP through XBMC), it's definitely taken some tinkering, and you still run into edge cases and occasional crashes.

Having used Kodi for close to 15 years (from XBMP through XBMC), it's definitely taken some tinkering, and you still run into edge cases and occasional crashes. However the Kodi team has made an amazing job simplifying installation on numerous platforms, to the point where the most advanced thing you need to know is how to use a USB stick and 7-zip. If these people (box sellers) ship it with a remote control, and a self-contained Kodi distro (Ubuntu), I have no problem seeing anyone using it intuitively as plug & play. Maintaining is mostly an issue with your own library in my experience. If that part is outsourced to third party plugins there's not much to maintain. Though if that plugin breaks/is forked/whatever then you're boned. I really feel for the Kodi team though, getting blame for piracy, numerous support requests stemming from unaffiliated third party plugins, and all for an amazing open source product they've made for free.