Lubuntu is really like "teaching a man to fish". If you give them instructions on how to install it, then suddenly nobody will ever need a shiny new $1700 macbook to get started with basic programming and content rich web browsing.
Though personally I prefer text :)
There's an app store and browser add ons work well.
The hardest thing for a casual user to learn would be "sudo apt-get install" and then guessing what the package name is that they might want to download, like vlcplayer or java
Everything you said in this sentence is a deal breaker for a casual user, and a terrible user experience in general.
Linux takes time. Life is finicky. But for the average Thai person or Vietnamese living on $300 a month, a $100 investment is more palatable than $600
Chromebooks are targeted towards college students and websurfers are they not? Lubuntu is perfect for them, especially, if they don't have $600 to shell out on a Chromebook.