The general perception is that they're learning institutions, but that couldn't be further from the truth. In reality, bootcamps are technical recruitment agencies.
Companies are realizing that smart, motivated people with no CS degree can still oftentimes excel in the majority of positions (primarily app development.) The problem is finding those people. Bootcamps have stepped in to bridge that gap - they essentially screen for people who learn quickly, teach them the bare essentials, and send them on their way.
This means bootcamps have a symbiotic relationship with the quality of students they're able to attract. The best bootcamps turn out the highest quality students, who then get the best jobs, which makes the bootcamp look better.
Dev Bootcamp was always in that awkward position where it was trying to be one of the "premiere" bootcamps, but never actually made it to tier 1 status. It's always lived in the shadow of Hack Reactor, Fullstack Academy, and to a lesser extent, App Academy. Having personally worked with Dev Bootcamp graduates, I've felt that on average, they were much weaker than the graduates from the other bootcamps I mentioned.
Since Hack Reactor in particular has been expanding its reach to additional locations, Dev Bootcamp was probably getting boxed out of the premium bootcamp space. The founders were unwilling to be relegated to tier 2 (or the demand was dropping too fast) so they had to pull out.
It's a shame, but I can't say I'm entirely surprised.