This is due to the issues of loyalty, being accustomed to a certain interface and navigation structure. Customers want simplicity and speed. Often, they have employees in their company in charge of finding the best company, even on the web. The average household does not have this person. Because he prefers the phone over e-mail.
People have to understand that e-commerce represents a real chance.
Mentally, one really needs to start yesterday. But do not forget to make sure that your business partners are following you. Once one knows what one wants, there will be very capable people around who can implement it. But there is no single or general solution. Every company has to figure out the right strategy for itself and then implement the technical solution.