... You think Mozilla don't focus enough on Firefox, so you think they should spend more money on Thunderbird, which is an app in an almost-nonexistent market (desktop email)?
Some folks are just never happy with Mozilla.
Firefox has massively improved in recent years. WebExtensions being async prevented horrific freezes that used to happen. Rewriting components in Rust, and using web assembly for native libs, are both good for security. And WebRender was revolutionary.
Two decades ago, Thunderbird was in the single best position to provide an alternative to Outlook. Now, not so much. If they'd had the foresight to do that two+ decades ago, they could be in a similar position to Google Docs or O365 today in terms of revenue generation.
They're a bit behind at this point on what people even like in a browser. They should focus on the core technology. I think dropping Servo and the Rust efforts was probably a misstep and burning cash on marketing and buying out unrelated companies altogether doesn't help.
edit: Also, Thunderbird doesn't HAVE to be just a desktop email client. If blackberry had developed email clients for iOS and Android early on, they would still be relevant today.
Mozilla org has completely lost sight of their base. A good 70-80% of their budget should be on their core product development and adjacent products only. The fact that only recently have they discovered, hey, we had this pretty good email client that we let all but die off.
They should separate their core rendering and script engine teams to focus on better embed-ability and security structures. Another team(s) focused on the integration for Firefox as a browser. Another for Thunderbird. The fact that they killed off their Rust efforts, XULRunner and so many other things that could be really useful today is just painful.
Yeah, XUL didn't run great on 1998 hardware, but what are so many apps targeting today, Electron. And now there's a resurgence towards lighter options (Tauri and others) because it kind of makes sense to (re)use a browser rendering engine for general UI development. It's extremely flexible, has a flushed out (if somewhat complex) styling and theming system, multiple language support, complete font rendering, svg rendering, and accessibility support and runs on/under everything under the sun.
Maybe hire on some of the types that have tried and failed to remake email and browsers that have some creative vision on how users actually use these applications, and let them work with the engineering teams to make quality software again. Spend less time on branding, and more time on the core tech. They still have enough brand reach and clout that people will try the new stuff and if it's good, then organic growth can and would work (again).
Hell, if they want to branch out... make a REALLY great email and communications platform that is open-source with a hosted model. How big of a pain is it to self-host many of these things today? If they want to acquire someone, bring in Caddy, Fastmail and/or Zimbra for adjacent tech development.
I only harp on the email and Thunderbird side because two decades ago, they were in a better spot than anyone to offer a competing product to Outlook+Exchange and they just didn't even try. And now even Outlook kind of sucks because the cloud integration is what it is at scale. Leaving a gaping hole where that entire market used to live. A great open-source core product, with a good extensibility model and some commercially licensed integration points could have been insanely popular.