The Consortium is trying to limit the number of emoji it adds each year, and there isn't much incentive to add flags that won't see widespread adoption. Flags are 'by far' the least-used emoji, Unicode said, and aren't even used that often in social media bios. Moreover, Unicode can't remove a character once added - while it can update emoji, it's hesitant to add a flag that might not last long. The Consortium noted that flag additions tend to 'emphasize the exclusion of others.' If the emoji team added regional flags for one country, for instance, it would highlight the lack of regional flags for other countries. They're more trouble than they're worth, the organization said, whether it's the inherent politics or the value they bring.
The Unicode Consortium has warned it will 'no longer accept proposals' for flag emoji, regardless of category. Don't expect to see new flags in your phone's emoji any time soon.