Ask HN: How would you convince a client to go through digital transformation?

Situation: You have a client who has a successful business based on physical products, a good supply and distribution chain. However you know that digital transformation is important for them to succeed and prosper. The managers are all from a different era though, and regard the Internet and e-commerce with suspicion because most of their business still comes from offline.

How do you convince them to invest in the newfangled Internet thingamabob?