Should we start learning Javascript once again?

Hi Everyone,
with HTML 5 being adopted by more and more browsers out there, with DailyMotion releasing an HTML5 version of the movie profile page, and YouTube doing the same; there comes a question: should I get back to learning Javascript?
The posts on the subject abound all over the internet:
HTML 5 versus Flash / Flex

Digital [...]

Study - The Video Players of Social Networks (YouTube, DailyMotion, Veoh, Vimeo, GoogleVideo, Flickr)

Hi Everyone,
I am doing research on which video player I can easily embed inside of an AS3 application. I had these players in mind: DailyMotion, Vimeo, Veoh, Youtube, GoogleVideo, and the DivShare player as a fallback. Right of the bat, the following players are still in AS2:

YouTube
DailyMotion
DivShare
GoogleVideo

While these are in AS3:

Vimeo
Veoh
Flickr