There's been some discussion in the Facebook group where a bunch of people wanted various info about jobs in the tech industry.
A lot of people expressed interest in asking questions and a lot of people expressed interest in answering them, so I thought maybe the forum would be a better venue for this than a Facebook comment thread. So, ask away! I'll come back to answer stuff later today. (And hopefully some other folks will too so that it's not just my perspective!)
Employee #100 seems a bit implausible. If you joined Dropbox as employee #100 it would be in early 2012, at which point they had just gotten a $4B valuation. It's only gone up 2.5x since then--a mere 35% per year--so you probably wouldn't have done better than a founder over the equivalent timespan. Especially once you take into account the many worse options that were in Dropbox's reference class in 2012, like Fab.
That said, I agree that trying to forecast startups is probably a useful exercise--and maybe even possible to do historically, if you're interested in ones as high-profile as Dropbox. It's an open question to me how efficient the market is here (i.e., are companies with semi-obvious predictors of success likely to offer less equity).
I heard a rumor suggesting Dropbox was slower to hire than the typical tech company (i.e. a $4B company with <100 employees is somewhat atypical even in tech), though this may be what the norm is trending towards.