mct16:
Director-for-hire? You make him sound like he was just an extra from a local actors' agency.
Hard to believe, I know, but that was more or less true at the time.
I go into it in more detail in the post I linked back to, but this was far from a joint project. It's easy to dismiss as a one-off failure with hind-sight, but
1941 just about sank Spielberg's career as a movie director; he was regarded as being profligate with money and time, and no studio wanted to work with him.
In fairness the greatest problem was the gap between expectation and performance of the film: it wasn't that it didn't make money, it just didn't make nearly as much money as the studio had
anticipated. At the time there were dark rumblings that
1941 could have bankrupted the studio - fortunately this didn't come to pass.
However, it was felt by many that the wunderkind had crashed to earth with a bang, and Hollywood was fairly fickle in dropping him on that basis.
mct16:
the sort looking round desperately for work.
He was - he couldn't get a film project at the time.
Only because George Lucas personally guaranteed that he would vouch for Spielberg, covering any extra costs himself if the film went over time or budget, was Paramount prepared to have Spielberg involved.
Spielberg was adamant that he could do it, that he would stick to the script and get the film in on time and on the money, and thus, yes, to all intents and purposes he was a journeyman director on Lucas's payroll for the duration.
Also as mentioned, apart from having had a converstaion about it on a beach in Hawaii while on holiday, where Lucas told Spielberg the story (at which time Spielberg suggested that the character be called Indiana
Jones rather than Indiana
Smith), both Spielberg and Lucas have said that that was the extent of the "collaboration" and input - the rest was down to Lucas and Kaufman's story, and Kasdan's script.