On the one hand Mozilla needs to make money somehow, on the other hand, this does feel tacky. What other alternative is there that would actually be sustainable for them?
What is the approach that most nonprofits that you're referring to take?
The American Cancer Society convinced professional sports teams to wear pink for an entire month, the Goodwill collects people's unwanted junk and sells it, the YMCA recorded a song and choreographed a dance...the only approach I'm aware of that non profits take is the one that generates the most money..
The fact that Mozilla is a non profit and have built a product that performs on-par with products built by two of the most valuable companies in the world (Microsoft and Google) is astonishing. The engineers building Firefox cost the same amount as the engineers building Chrome and Edge. But balk all you want at seeing an adorable red panda fill up your screen
I'd love to do a shameless plug for radioparadise.com as a wonderful model of someone who does an extremely tasteful periodic reminder to donate :).