Still, Thunderbird needs a bigger vision. What does Thunderbird want to be? The cross-platform Outlook? Then merge Lightning into core. The native Gmail? Then get a conversations view. The backwards-compatible, easy, and secure mailer? Then merge Enigmail into core or make SMIME easy to use or get some Rust code in. The ultra-portable mailer? Then port it to Android and iOS. The super-flexible mailer? Then somehow help plugin devs.