Of course not. Google Wave is not accessible to people who barely understand e-mail and don't even use IM. (much less video chat, twitter, or any other fancy new communications mediums) As part of our normal lives we have to interact with these people on a frequent basis so you use the communication tools they are comfortable with. In small, technically literate, circles it may become a very valuable tool. In the real world people will still have to write e-mails. It's 2009 and I still have a handful of business contacts who reply to my e-mails with a request to call them on the telephone. This premise is a prime example of practical real world usage meeting carefully constructed bubbles of people who are highly prone to adopting new technologies.
No. E-mail is too fundamental.
We all love our text/plain communication, but it's the other 99% of internet users that drag us kicking and screaming into fads. I didn't own a mobile phone with video support until a few months ago when my sister had a baby and I was added to her daily video-update list.