Answer: It varies, and not entirely.
Explanation: Throughout the first decade of the 21st century, RBs and WRs consistently produced the most 30+ point and 40+ point one-week scorers. In the next decade, QBs caught up with--and at times overtook--RBs among 30+ point one-week scorers. From 2017 to 2020 specifically, such breakout performances have been pretty equally divided among QBs, RBs, and WRs.
Why This Matters: A monster game can make-or-break a fantasy week--and by extension, a fantasy season--depending on whether you or your opponent has the monster performer. RBs and WRs are generally higher injury risks than QBs, but they're also most likely to carry your team in any given week, reinforcing the special status they have on any championship-caliber roster.