If you're interested in maximizing income, I would rule out pre-med. It's sub-optimal preparation for any career except medicine, and medicine is sub-optimal for income. A few reasons:

Salaries are essentially capped by reimbursement rates and man-hours. The best surgeon in the world isn't going to make more than a few million a year doing elective surgeries twelve hours a day year round.

The things that generate the most income for rich people with MD's, patents and start-ups and C-suite gigs, don't require the MD credential. There are better stepladders. The possible exception is medical celebrity, but the odds of you being the next Dr. Oz are extremely low.

The average physician makes far less over his lifetime than he could applying the same horsepower and hours worked to, say, finance. It's a fairly straightforward back-of-the-envelope calculation. In addition to losing seven to ten years of income after college (residency only pays a little above living wages) and possibly incurring $250K in student debt when money means the most due to time-value, you'll graduate into a market absolutely determined (for very understandable reasons) to bend the healthcare cost curve down and pay doctors less. American doctors are currently paid much, much better than doctors almost everywhere else in the world, due in large part to guild-like protections, and this cannot continue indefinitely. Globalization's already lined up to crush radiology and elective surgery, two of the better-remunerated fields, and IBM would very much like to put oncologists everywhere out of a job. Another half-dozen specialties are in turf battles against mid-level providers like nurses.

All that said, I highly recommend medicine. Just not for optimized philanthropy.