This facile argument from Magento is correct, but needs amplification:
Adjacencies are not simply parts of the supply chain that can be consolidated and eliminated — though, in this case, Ikea is adding a layer of fulfillment, delivery, and assembly. Businesses with a solid trust relationship with consumers can expand into new, even largely unrelated lines of business with deliberation, especially deliberation that includes the customers. Finding new value isn’t merely identifying an “uberizable” service, it also requires rethinking the customer experience of the existing brand.
Early days, remember it is early in the on-demand evolution. Uber is not the model to end all business models. In fact, TaskRabbit went to great lengths not to behave like Uber toward workers.
The point of the IKEA example is that companies need to find natural adjacencies that enhance the customer experience. What opportunities do you see in your business to uberize your customer experience? How quickly can you augment, adjust or rethink your customer experience? These will be the defining questions for merchants in the next 12-18 months.