The best product idea on paper might not lead to the best product in reality.
Products that make it to market and become great do so because of timing and strategic fit to the companies who made them.
Regardless, much of their ‘greatness’ gets cemented long after launch.
A user-centred approach to designing products doesn’t guarantee that customers will love them. It just means the customer has been thought about in the process more than they might have been. It contributes to the quality and relevance of the product but it doesn’t guarantee success.