That's a great question, honestly, and I like your framing of trust.
I do not trust Mozilla to keep a product alive. I was frustrated by Firefox OS and more recently Pocket, but everything they've tried or acquired aside from the browser itself (and Thunderbird I guess?) has failed and been shut down. That has burned a lot of people along the way.
For this reason I can't see myself becoming a user of any future Mozilla projects.
That makes much more sense. I wonder what the non-HN public thinks - most of those products, like Firefox OS, were essentially unknown outside HN-like populations. Pocket was better known.
But yes, that is part of trust and I'd like to see them address it.