The only difference between "rich text" and what you can do in a terminal is changing font families/sizes. And that is not even close to useful enough to justif

The only difference between "rich text" and what you can do in a terminal is changing font families/sizes. And that is not even close to useful enough to justify runnig a terminal on top of a browser. As for familiar HTML, it is trivial to write a library that accepts "familiar" HTML and converts it to SGR cdes for formatting. I could do it in an afternoon. And for "awful slow", do the following experiment. Open a large text file in less in your terminal. Then scroll it continuously and monitor CPU usage (of the terminal and X together). Now compare with a real terminal. Think of all the battery life and all the energy you are sacrificing just for the ability to use multiple font sizes and families.