Mika,
Somehow I don't think anyone here cares about what you consider art and what you consider a snapshot. You really need to stop worrying about how crappy other peoples photos are and worry about your own. I do have to wonder if any of the shots you've posted are your own or if you have misappropriated them from other photographers without giving them proper credit.
If the former, and they are your own photos, then nothing in them beyond the shallow DOF and bokeh is anything special and the only thing I see of note is in the one of the girl walking by the storefront with what appears to be grain in the face of the out of focus man in the foreground. This tends to indicate that it is a film photo rather than a digital one. It IS hard to get grain out of a APS-C sensor, but it is just as hard to get it out of a full frame sensor, so I don't see the point of posting a film photo to gripe about some quixotic battle you have embarked on between APS-C and FF.
If the latter, and they were taken by other photographers, then the only thing you are again demonstrating (besides not understanding IP rights) is that your idea of a "non-snapshot" photo is shallow DOF and smooth bokeh (and perhaps "grain"). This tends to indicate that your idea of "art" is rather specific. Not "wrong" mind you, because art is in the eye of the beholder, but I do consider it sadly limited.
What I don't understand is why, if the sensor cannot produce what you crave, are you using Pentax DSLRs. Hoping for an eventual FF platform? May happen with Ricoh at the helm, but I'm not counting on it with the 645D available. Perhaps you should just sell off all your Pentax gear and buy a FF Nikon or Canon. Then every photo you take will become "art" and you will make skads of money. Then you can buy Pentax and smash all the APS-C sensors and start making FF cameras.
Mike
p.s. flickr is a poor poor place to find anything other than snapshots anyway. While some good photographers do use flickr, the shots there are mostly casual, so do not lend themselves to an analysis of the capabilities of something like APS-C vs FF. I suggest you surf some real photo sites, like
photo.net,
zenfolio,
smugmug, or the like.