Wave requires a new way of thinking. Sure, we're capable of it as humans. But... we like linearity...
RSS is one of the greatest Internet innovations of the last decade (thank you Dave!). So why did it never take off with consumers? Simple... It only solved problems that some, eg info junkies, had. And it required a new way of thinking and operating...
But what about Gmail you say? Gmail too was a complex beast when it debuted with its conversation views and interface - and it caught on. Yes, but Gmail was different. It solved problems: mail storage quotas and killer search. Thus people were willing to make the investment to master it.
