For example, it's widely understood today that Firefox has a much smaller share of the market now than it did a few years ago. Most measures I've seen show a drop from somewhere in the mid 30%'s down to under 20% today. Proportionally fewer Firefox users means less influence over the future direction of the web, of course.
SeaMonkey never really had that much penetration to begin with, and still remains basically irrelevant.
Firefox OS doesn't really seem to be taking off. While it may sound nice from an ideological standpoint in terms of openness and standards and all of that, in practice it doesn't sound very enjoyable or practical to use. I've seen enough people show displeasure over the low-end devices it's commonly used with, with the highly restrictive development environment (being forced to essentially use JavaScript/HTML5/CSS for apps), with a lack of features, and a lack of apps. Those are very serious and fundamental shortcomings.
Thunderbird and Persona have both been "turned over to the community". That appears to be a polite way of saying that Mozilla has given up on them.
Asm.js is pretty unremarkable. It's a human-unfriendly subset of JavaScript. NaCl is a much better approach that would ideally be adopted by the major browsers. Unfortunately, we've seen nothing but hostility toward it from Mozilla.
Rust sounds appealing, but it's not really usable today. We keep hearing that there will be a stable release sometime later this year, but we'll need to see that actually happen first before it'll have any chance at being widely adopted. Even then, it's doubtful Rust alone will have any major impact on the web any time soon. Servo may, but that's clearly very much also an unusable work in progress at this point.
So overall, I don't see Mozilla as heading in a very positive direction. They really haven't had any wildly successful new offerings in quite some time now, and what they have been working on lately doesn't seem to be getting all that much adoption. Without a large base of users, their influence over the development of the web will just get weaker and weaker.