If I were a math grad-student type and actually had the talent and skills to get into a high-paying quant job, I'd consider doing the job for something like five years, saving everything I can, and then leaving for more fun jobs with the option to live off the investment income from the savings whenever I don't feel like working for a year or three.
If the salaries really go to $400k, saving up a million in the five years seems possible, and investing that with 5% annual return would give you a quite nice for the math grad-student type $50k salary for free.
They may go to $400k, but not until you have significant experience in the field, so you five year would be more like 10 years. Then you have a family, health insurance gets pricier, and so on such that $50k a year doesn't look that attractive anymore...
I did guesstimate that in. You'd only need to save an average of $200k per year to get to $1M savings in five years, you can do that before you hit the $400k rates.
I'm not really familiar with US costs of living, where I come from $50k is an upper middle class salary. Quick googling got me 5k as the ballpark for the health insurance fee for a single person, and with a family you'd probably have a spouse chipping in, so that doesn't look like a dealbreaker. Housing is tricky, apparently "live in an apartment, don't have a car" doesn't work in the US for some reason. You could always move to a rural area with cheap housing, but that does get a bit extreme, and then you'd need to figure out the costs of getting everywhere by car.
If the salaries really go to $400k, saving up a million in the five years seems possible, and investing that with 5% annual return would give you a quite nice for the math grad-student type $50k salary for free.