Yeah $200k of savings in 4 years is maybe $40k/yr of savings, plus optimistic investment returns for the first 3 years. But GP also mentioned all loans paid off, so that adds another $10-20k/yr, depending on what their loans look like.
It's not impossible to save that much money straight out of school, but if you're making that much then you could still save a decent chunk even if you're paying $2k/mo for an apartment (which comes to $100k over 4 years).
Several of my young amazon coworkers had 500-800k at 4 years out of college with the stock going up. One basically retired (he is very frugal and allergic to everything and never goes outside) at 4.5 years.
It's not impossible to save that much money straight out of school, but if you're making that much then you could still save a decent chunk even if you're paying $2k/mo for an apartment (which comes to $100k over 4 years).