Sr. Software Engineer at Google, on average (sample size of 189) make $145K on average with $63K bonus for $200K per annum.
So for an average equity of 1.125% for developer (according to angel.co) and average salary of $93K, a startup has to make a non-diluted exit of 8.56 mil on the first year, 17.1 mil on the second year and 25.6 mil in the third year to justify the opportunity cost.
Of course, not every developer can make $200K per year but just food for thought of working for startup vs. BigCo.