A tweet from a Ph.D. candidate at Princeton University announced on Tuesday that graduate students at the school will receive substantial raises for the following academic year, and a statement from the university’s office of communications later confirmed the news. Graduate students who currently earn $36,570 over 12 months (plus a waiver of tuition charges amounting to tens of thousands of dollars a year) will soon be earning $45,600.

The news reminded me of my own experience in graduate school in the mid-1990s at Michigan State University. For much of that time, I earned approximately $12,000 a year (plus a tuition waiver), which comes out to about $22,000 now. So things are definitely looking up for grad students, no doubt in large part because of unionization drives at campuses around the country. It would never have occurred to me to demand higher renumeration in return for reading books and trying my hand at producing scholarship for five years, but a higher income would have undoubtedly made life easier back then. I certainly wouldn’t turn down the increased salary if I were a grad student today.

But would I have been offered such a salary? As I said, I didn’t attend Princeton, and though things have improved across the board, they haven’t improved equally.

Plenty of Ph.D programs still pay comparably to mine, now offering in the $20,000 to $30,000 range, while Princeton (like Yale, Stanford, and other top-ranked schools) pay a lot more. But of course, students at those most elite universities already have a much better chance of landing one of the very few tenure-track jobs available once they complete their studies. (You’ll note that I, your humble Ph.D.-holding scribe, am not a tenured professor.) Could Princeton’s voluntary salary boost be just the latest example among many in the U.S. of the privileged few receiving ever more advantages while those lower on the hierarchy find themselves sliding ever further down a slippery pole?

If you’re a grad student at Princeton, congratulations on your big raise. But if you’re studying elsewhere, at a school that can’t afford a splashy 25 percent stipend boost in a single year, don’t let stories of nearly $46,000 a year inflate your hopes. There just aren’t enough slots at the top for everyone.