Half of the joke about the color of the bubbles is that the green bubble people are either ignorant of or disregard the improvements in texting for the last decade.
No, the joke is that people keep paying absured amounts of money for apple products while thinking that it was the other people who were ignorant of or disregarding said advancements, when in reality it was Apple refusing to let anyone else implement those advancements in a way that worked between platforms, and it was Apple refusing to implement anyone else's version of those advancements.
That's the real joke.