Those are not assumptions. Historical precedent is on my side and there is no shortage of examples: Feynman, Einstein, Grothendieck, Newton, Pierce, Hamming, Margaret Hamilton, Leslie Lamport, Barbara Liskov, Rich Hickey, and on and on. I think it would be foolish to argue that those individuals have not contributed in significant ways and they have all accomplished those contributions in academic and non-industrial settings. Rich Hickey even has a talk where he explicitly mentions the fact of needing long hours of solitude to think about things.