The comments state that there was no staging or test environment, no ability to roll back releases, refactoring was a dirty word (engineers wanted to refactor, but couldn't), principal on technical debt was never paid (only the interest in terms of hacks to make the site scale-- again, product organization prioritized new features).
The rest: location, technology choice aren't sufficient to "kill" a company: there are successful companies in LA, there are successful and agile companies using Microsoft stack (where appropriate-- see Loopt and StackOverflow/FogCreek as examples of companies using both FOSS and .NET). On the other hand, they're not optimal either: they aren't what engineers would choose themselves most of the time.
This indicates that the technology and location choice aren't the cause, they're symptoms of company management that doesn't understand building non-trivial Internet applications (what the optimal technology stack for one is; where, when and how to hire developers to build one) and yet maintains authority to make all technical decisions. Contrast this with Facebook, Google et al-- where every process (from corporate IT to production operations to HR and recruiting) is designed with needs of the engineering organization in mind: "Want two 24" monitors? No problem. Want Linux on your laptop? No problem. Want ssh access to production? No problem. Want to fly in a candidate to interview? No problem."
[1] I personally wouldn't touch Windows with a sixty foot pole, but speaking objectively C# >3.0 and (especially) F# are great languages.
[2] "They weren't talented": having interacted with some ex-MySpace engineers, this just isn't -- at least universally -- true. Indeed, here's a secret to hiring in an early (Facebook in 2005) startup: seek out great developers who work for crappy companies, people who have joined "safe bet, resume brand" companies like (post ~2003) Google aren't likely to join you until you've already become a "safe bet, resume brand" company (Facebook in 2008-Present).