iTMS is a store, just like Amazon.com is a store. For a music industry to be frightened of any outlet that sells millions of units of your product is a bit bizarre. Apple are surely only putting up for sale all and any decently produced music that they can get their hands on in order to attract people to their site - the lure to iPods. Apple must surely be at liberty to set out their store however they see best, and take account of the needs and expectations of customers, suppliers, and programmers/site designers.
But on the supply side, the music industry is setting all the rules (with a little guidance on DRM from Steve Jobs) The big five model at the moment means the big five can dictate pricing. ie Apple are playing by the financing rules of the music industry, sending them, is it 70%? royalties on all sales etc. Likewise the big five control the artists who are tied to contracts, so however much an artist thinks it is neat to go straight to an iTunes shop front, they cant go independent till they are out of contract etc.
But the fear for the music industry must be in terms of changes from within the music industry. ie If artists see the value of changing their ways dealing with labels and eventually go independent to get more control of their music, and see the iTMS as a good outlet for their own music, so be it, Apple will offer their store as a platform, but the iTMS will just sell music from sources that reflect changes made by artists and execs within the music industry.
On the surface at the moment it can't be in Apple's interest to actively change the way record industry works, nor even make incy wincy rumour noises about signing bands up, else they will instantly lose all the music from the big five and be stripped down to an independent label music store. So iTMS will stay a bit of a puppet to the big five, ie nothing to be afraid of - unless of course the stats show that the independents song sales are strong enough to keep iPods sales strong, then who knows what Steve Jobs has up his sleeve for the next revolution in how music is sold.