So I did a mini research project on Claude to answer your question. From 1900-1930, 87% of Nobel Prizes in Physics, Chemistry and Physiology/Medicine were awarded to individual contributions, 13% were awarded to collaborative contributions.

This ratio has flipped in the past 30 years, from 1994-2023, where 17% prizes were individual, 83% collaborative.

So I'd say yes, collaborative work is increasingly a requirement to do groundbreaking research today. The organizational structures and funding are a part of the reason as you mention. But it's also that modern scientific problems are more complex. I used to have a professor that used to say about biology "the easy problems have been solved". While I think that's dismissive to some of the ingenious experiments done in the past, there's some truth to it.