Much like that/those quote(s) are trying to explain, I myself, too, would much prefer any artist to improve his or her abilities and knowledge regarding art, than to stick to the same methods and choose not to improve only to retain recognizability and consistency in their works.
But aside from that, I think the real issue you're getting at is what makes style identifiable. Going through ptoing, big brother, iLKke, Syosa, Dex, Skeddles, 4tochkin, scruffs, and Fools work, an example collection of artists whoms 'styles' I find easy to identify, I think it's a safe assumption to make, that this stems from the lack of experimentation, or at least, what was seen of their submitted work.
Most of these artists tend to stick to the same methods, tools, and even colors, that they're comfortable with, and most of these artists are very much seasoned, and this combination of tools and methods is the way they feel they can produce the results they are most satisfied with.
When I look at your gallery, I see someone still learning, trying out new things. Just have a look yourself, compare your galleries with those of above mentioned artists and you'll find what I say to likely be true. In your gallery, I see pieces that are very detailed, although limited, or pieces that are detailed, without any set restrictions. I see works of art that are wide-pixelled, animated, simple, and just plain unusual. (Such as the Anti 2D fighter.)
Now without a doubt, it is a difficult task identifying the style of someone, according to a preview of a piece that could have many different restrictions. In other words, it's hard to know when it is your piece, if you may be trying new things. If it's only PJ-preview-related, then you could benefit from adding a unique border or element to each preview, such as Elk and JinnDEvil have done. But otherwise, I don't believe your style will ever be condensed as long as you're trying out new things, as opposed to doing the same thing over and over with only a change in subject.
I suppose the best way to sum this all up is, not that you lack a distinct style, but possess many different styles, that are only defined by your work methods and tools.