Good questions.
I'm concerned about Mojave because it's the last "official" Mac operating system for my upgraded 2010 Mac Pro. My machine continues to work just fine while I wait for the Apple Silicon Mac Pro, but its operating system needs a little help from Apple to keep it secure while I wait.
When I moved all of my business and family devices to Apple a dozen years ago, privacy and security were important factors. They still are, and I've happily paid Apple's premium margins on the many products I've purchased from them because I believed they understood this and would always act accordingly.
If Apple "orphans" my Mojave Mac Pro, just months before the Apple Silicon Pro is available, it will send a clear message that my commitment to the Apple ecosystem was misplaced. If that's the case, it's fine and I'll live, but it will also be fine for me to explore other options for my computer purchases going forward.
I explained this to Tim Cook in a polite note to his public email at
tcook@apple.com. If you have similar concerns, it might be good to send Tim an email, before the short-sighted bean counters screw this up beyond all recognition.