I am not your target audience, but you are doing a good job on the tagging-front, so it's not that. You also seem to mingle with the community, explore the site, engage with the submissions of other artists...
The only explanations that I can come up with are that the Newgrounds audience in general isn't into video-gamey sprite animations or that you are uploading at the wrong time for your potential core audience to notice your works. I couldn't tell you what the "good" times are, though.
Gekkotsuki
Hmm... You know, It's not like I'm someone 'important' to say this or anything like that, but I think that the problem you have here (putting aside your clear lack of 'self-trust' talking about your future regarding the 'fame' of your account) is that you need a change.
"Huh? And what kind of?" - you may be asking to yourself. Well, I think that the answer is quite obvious; a change of content. I've just given a quick 'glance' to all the submissions that you have been sharing during all this years, and they all focus, basically and practically, in the same thing: '8/16 bits' (putting the Megaman vs Zombies submissions as a some kind of 'exception') animations about Sonic, Megaman, Plants vs Zombies, etc... In essence (and no offense, but it's the truth... or, well, at least it is, under my 'humble opinion') 'low-refreshing' content from your part that has made you get 'stuck' about getting any possible level of 'further-popularity'.
Why don't you simply just... I don't know, try something 'new'? Perhaps, that could be the 'key' and the solution to your problem; a change of content 'outside-of-your-comfort-zone'.
Give it a think.