Building digital disruptive growth engines for retail

I got a little excited last week when I read that John Lewis are opening an innovation lab. Opening such a lab was a recommendation from my research into disruptive innovation in retail. But what does it take to open such a lab and what challenges are businesses likely to face?
JLab isn’t the first. Argos also recently created a “digital hub” to spur retail innovation. But why create a separate skunk-works type business unit? Clayton Christensen (the father of disruptive innovation) certainly recommends this approach. He calls it the disruptive growth engine which is made up of the following components:
This model would present a number of challenges for many businesses.
How do you justify the investment before it’s required? How will a busy senior executive run and protect the growth engine over the long-term? Is it viable to pull your best employees from their day jobs into a disruptive growth engine? What do you do to change the culture of the business? How do you make the innovation lab accountable whilst also recognising the long-term strategic imperative?
Jeff Bezos has some words of wisdom:
The logic seems to be that in order to win the disruptive innovation you need to build something completely separate from your day-to-day business. I don’t disagree with that but it seems that having a Bezos-esque CEO who is willing to make major long-term bets on what could be next is critical.
Your thoughts?