Let me first clarify, and give an overview to what the 360 deal means. That means the label gets a cut out of every piece of the pie. Record sales and spins, Merchandise, ringtone, and tour revenues. To a varying degree this can be lucrative for the label depending on how much extra income the artist can generate. The bad part is that it limits what the artist gets from his hard work or effort.
This used to be a decent deal for just about everyone because labels were interested in finding and developing talent. They would do everything for you with no problem. However, now we are in a more independent era, the labels are used to finding artists who have the ability and desire to do their own marketing and promotions (most learned out of a necessity because the labels would not give them a shot initially). So why would an artist take one of these deals unless they don't know any better?
The Poster Children for Not Knowing any Better
One reason might be in order to learn. Especially if one has the ability to have a career that lasts more than 3 albums. Being able to gain the experience and connections from watching major label people at work could prove invaluable. If you are someone who has the talent to pull off several albums, this could also benefit as you become a huge star to not have to be hands on in every facet. The label also has more of an incentive to make sure that you are successful because they have a lot of income riding on it.
Now is this the most beneficial arrangement? No. However in life some sacrifices need to be made to get anywhere. I would much rather from my standpoint as a fan be able to have an artist put out great material because they aren't trying to save money on tracks or promotion and cannot focus. However, as a business man, I would consider the 360 depending on my freedoms to do certain things. For instance, I could sell shirts of my own design out of my home but the effort it would require would be counterproductive. Thus, I use a hosting company that does the work and I just toss up designs and when they sell, they sell. It works for me in that facet.
I have a concern that a lot of people take on things they are not capable of just because they want to be in control of everything and close everyone else out of the "loop". There are plenty of people who could be good executives if they could focus on that, but instead they attempt to be hybrids and the other aspects then suffer.
Sometimes you should to give up control and maybe some money in order to produce the best thing possible, not just enough to get by.