Could part of the pattern for requiring an email address (or phone number) at time of purchase be reduced customer support costs for the vendor. With an email

Could part of the pattern for requiring an email address (or phone number) at time of purchase be reduced customer support costs for the vendor. With an email address the customer can reset their own password for using their account with self service features - like get a duplicate invoice or view/change/cancel a reservation or similar stuff. Without an email address / phone number / something to link a customer to their order, the customer will need to phone up a call centre or visit a store or use live chat to get what they need. Southwest probably have a call centre or live chat anyway. Dominos have stores (and presumably a customer service department) and a pizza order is probably only interesting for a short time. If the customer can't sort their order out or get it sorted out, they will complain or give bad feedback. Even if it was their choice not to leave an email as they were too busy. Your business without any of these things has no incentive to get them if it can just collect emails instead and let users use self service features. Even if you already have call centers / live chat / stores then your cost of dealing with the customer via a self service portal is probably way cheaper than using them.