The fact that there's already entrenched photo sharing kings means that you don't have to be first to market, overspend, or rush. There's no time crunch here, meaning that a great product could have been built well - over time - on budget, and still have had success.
Did you even read the article? The photo storage / sharing / librarian market is HUGE. Definitely large enough to support multiple players, even marginal ones that make $3-400k/yr.
Why should these employees need to receive half pay when there is opportunity for them to receive full pay working on a different problem? I'm sure they could make great waiters at a local restaurant and receive a livable wage, but is it the best use of the opportunities they have? I'm going to go out on a limb and assume those 6 employees were excellent given how well Everpix was run.
Yes, you're right. But does a photo sharing service really need those kind of employees? Is there a need to be located at a technology cluster like the SV where developers are expensive and a scarce resource?
Services like Everpix are - in terms of technology - pretty trivial. They can be built anywhere in the world by average developers. No need to hire expensive Stanford PHDs to do a job a kid from the local community college in Kentucky could do.