Btw.: The historical side of the issue I would like to discuss here
This raises Two Questions:
So my motivation is to develop better intuition how much "non algebraicness & pure topology" sits in connectedness & irreducibility of varying fibers. The at least for me the cumbersome point is that in most contemporary literature one deduces ZCT - a statement purely about topology - as consequence of intrinsically algebraic Zariski's Main Theorem resp. prorties of maps of Stein decomposition. And I'm wondering if this statement - which is purely about topology - cannot be deduced with "almost" pure topological methods.
The historical side of the issue I would like to discuss here