I enjoy Keynes on this in 1930 -- http://www.econ.yale.edu/smith/econ116a/keynes1.pdf -- remembering, of course, that unforeseen economic shocks make predicting the course of implementation nearly impossible. In his case, it was WW2.
1. The definition of an "experienced" developer is subjective and varies widely. Startups with younger management may (incorrectly or not) apply senior labels to candidates with fewer years of experience and lower compensation expectations.
2. Anecdotally, I have seen startups in SF/NY take advantage of the lower earning expectations of candidates who are relocating into those metros and aren't prepared for the sharply different cost of living. There are places in the US where $90K goes much further and is a more competitive offering, especially for those who are willing to take less cash for the opportunity to work on something exciting.
3. "Developer" is a huge category. Some technical skills are far more scarce than others.
Publish a friend's political writings at MetricHour.com, split the AdWords revenue. Learned a bunch about Handlebars and the Ghost.io CMS in the process.