I have to agree with most of your points, but then again, I have to disagree on a few. For one thing, I've tried playing turn tables, and it's $&%*^# HARD. lets see you put down a needle down on a specific part of a record 100% of the time. Or mix two records together in front of a few thousand people (in perfect time with eachother). The fact is some DJs spend hours praticing, finding new sounds and textures and mixing two records together to create new vibes. We all need to accept that new instruments will be invented or created, and that music is going to change to incorporate these new sounds. Then again, their's alot of people just kinda riding the trend, but time will weed them out just like in any genre of music. As for the machine point, well guitar is a machine too.
However we do find people today taking a 30 year old peice of music, copying the sheet music into a MIDI application, deciding what synth sounds they like to hear, then adding a tired 4/4 techno beat with a few tired samples. Or how about a band playing actual instruments who just takes a couple of parts from a few say, an Alice in Chains songs and call it "Voodoo." Maybe it's a band with one guitarist who lays down 6 guitar tracks in the studio, isn't this all just as bad? Possibly worse?
I think the inherant problem we have to deal with is this is art, and nobody can really referee art. But we all feel just as bad when we spend years rehearsing, invest thousands into promotion, equipment, and recording, and then only 30 people show up at the gig. It's called paying our dues, and those of us who can stick it out, attract a crowd, and one day make it to the big time can atleast have the satisfaction of saying, "hey, I did my thing and it payed off."