[IshKebab]

It would be complicated due to Mozilla's structure. Mozilla Foundation is a non-profit that owns the for-profit Mozilla Corporation. You can donate to the foundation but they can't use the money for Firefox.

But the fundamental reason is that donations are only ever going to be a drop in the ocean. Google gives them $400m/year. Mozilla Foundation donations are like $3m/year. Even Wikipedia donations are only about $100m/year and they have way more users and push really hard.

[abdullahkhalids]

What's preventing the Mozilla Corporation from selling "e-merchandise", like a sequence of themes for $1, $5, $10, $100, etc, to raise money?

[IshKebab]

Probably nothing, but again I suspect they don't bother because it would be a drop in the ocean and certainly not worth the "Mozilla is selling out!" backlash you'd get from the sort of people that use Firefox.