Want a TLDR version? The gist is that unlike the traditional musician business model (get discovered, get a large amount of money up front, produce shippable versions of your product), they actually - ya know - work for a living. DMB incrementally grows their fan base by constantly reaching their customers directly, and selling them shows instead of records. And while the "record" business is dying, music isn't going anywhere. Satisfy a core customer need, work your ass off, and you have a viable business. You don't need to go raising tons of money to have a huge reach.
Yes, yes, yes. Music groups are small businesses and bootstrapping is now a model that makes sense for many of them. But although there are many parallels between musicians and startups (labels are the VCs of music etc.), there are some significant differences. For example, one of the tenets of bootstrapping is the pivot. If you're not profitable, take what you've learned and change your direction. For musicians this is far more difficult I believe. Like many popular artists, DMB's success stems from their unique 'sound'. This sound is a special mixture of each members personality and is very hard to change up while still remaining genuine. Founders certainly have a similar effect on their startups product, but I believe its far easier to hire a new designer than to stop playing the music you feel in your heart.
tl;dr - Music is business but its also an art. There needs to be a new bootstrapping methodology tailored towards music.
Re: Bands Pivoting - Happens all the time. They try out new drummers, new singers, new bass players. Sometimes they go solo. They keep experimenting, either with their style, or their bandmates, until they find something that works for them - both artistically and commercially.
Sometimes it never goes anywhere - but that's true of startups as well.
Hmm, what other thing does this sound like?