Small fish in a big pond? I've heard a completely opposite advice stating that "in a big pond" there's much competition, and dominating a small niche yields better results. What is the rationale behind being a small fish in a big pond?
Once choosing to do more difficult courses at a more prestigious university. I don't think this was great on my well being in the short term (always feel like the idiot in class) but in the long term being associated with the brand has helped A LOT. So it was probably more beneficial to get worse grades at a "better" uni.
Professionally rather than being a gas data scientist in a small city, moving to a more competitive more established field of web analytics/marketing (with many more peers) in a larger city has lead to a much higher salary.
The big pond on the other hand, pays a bit more but is much less interesting. The big pond is almost certainly never going to dry up though.
A similar analogy is it's better to be the worst player in the best band than the best player in an awful band. You're going to learn less and learn it more slowly in the latter situation. I think this is more what the author was going for.