Hip-hop (mostly American hiphop that charts here; the "BritRap" thing tends to be more underground, more eccentric, and often not as violent) is a contributing factor, but guns have unfortunately become part of the "ghetto" image for many black men nowadays. There's probably a myriad of other causes which you listed, but they've all culminated in this image and this image seems to drive many black communities. Whether there's any stopping it is questionable.
At the same time, you can't really generalise with these things, because there are numerous successful black doctors, lawyers, and ironically enough, hip-hop artists who escape the ghetto mentality and live their lives within mainstream society without betraying their values and identity.
Without meaning to be vague, all one can really do is theorize.