EDIT: here, i'll do the simple calculation for you using the stock market average of around .08 returns per year and forty years till retirement. FV = 100k (1+.08)^40 is 2,172,452.15. There is a very small chance that the difference in salary will be that large between those two schools.
As Albert Einstein said "The most powerful force in the universe is compound interest".
Good luck getting an 8% return...
I do agree with your point. Investing the 100k would most likely be the prudent decision.