Here’s an overview of status matches, asking a loyalty program to give you status based on the status you hold with another program.
Travel providers are interested in acquiring their competitors’ best customers, but elite status has a lock-in effect. Sure, you might want to defect from United to American or from Delta to Alaska, but it’s pretty tough to do that and start from scratch with a new airline. You’re well treated as an elite, and it’s rough out there often times flying without any status.