You have to look at it context - not every market works as quickly as the consumer tech market.
In the vacuum cleaner market there have been two major revolutions in the last 30 years.
The first was the Dyson. It was launched in 1986 and has slowly taken over the high end vacuum cleaner market.
The Roomba seems to be following a similar path. I know a few people who use it, and it has been a huge success for the company.
