Sure but you only get one chance to impress. How many people will be bothered about trying Google wave again when they think it is ready? Still a mis-step IMHO.
Limiting access gives Google a good chance of introducing a finished product. Something that will impress. I very much doubt that Google would impress all that many people with Google Wave as it is now. Me, sure, but not my dad.
Also: invites are not that hard to get to in this day and age. So you’ll be able to at least invite a few friends.
