That's what I meant to say earlier, yes. Not only had he never written a feature-length screenplay before, he'd never actually read one. You're right, though, he'd surely been in the business long enough to know that screenplays aren't generally breeze-block sized epics packed with detailed stage directions and character backstories?…
In terms of length, I think he did – when Aykroyd delivered the first draft, he jokingly disguised it as a telephone directory.
However, having a rough idea of what the finished article is one thing, having the abilities and resources to execute that concept is another. My gut feeling is that there were two things at play.
One is how important this project – or rather the Blues Brothers – was to Aykroyd and Belushi. I had a quick look to see if I could find my copy of Wired, but will have to go from memory – one of the things that struck me in the book is how invested the two were in it. The film being a passion project is an understatement. When someone is that invested, I think it can be hard to have the kind of objectivity to decide what should (and shouldn’t) go in – that’s compounded by the other factor (IMO), his inexperience in screen writing.
If someone doesn’t have experience as a screen writer, I feel not knowing how much detail to go into or what information is superfluous, is a common issue. I think people to be surprised by how sparse scripts tend to be and requires a certain skillset.
Actually, I guess this is ties into a third factor – the film business. Although Aykroyd had experience as a sketch writer, to let him go off and write the script with no experience and no guidance was a gamble.
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He certainly did have an incredibly fertile mind, but I agree that he evidently needed someone to edit and hone his ideas into a filmable piece of work. I've only seen the first 30 minutes of Aykroyd's sole auteur effort Nothing But Trouble - I had to switch it off, as it was such a depressingly unfunny, nausea-inducing mess - but I think it's probably fair to cite it as proof that, when left to his own devices, he lacked the discipline to make a coherent film. An imaginative writer, no doubt about that, but some of his film ideas were over-ambitious and poorly thought out….
Hee, I’ve never seen that one. I’ve been put off but what I’ve heard, however, I’ve also read some more positive write-ups, so maybe one day….
…Which might explain the verbose, stream-of-consciousness nature of some of his writing? That can work within the context of a relatively short, offbeat comedy sketch - establish zany premise, milk it for laughs, then exit sharpish - but it's difficult to sustain that over the length of a film. The Pythons managed it, but they benefited from having each other as sharply critical sounding boards and editors.
Quite possibly – I would also say that from what I’ve read, I get the sense that the SNL material Aykroyd produced was written tightly as well as to a high standard.
It’s possible that when working in such a restricted format, he found it easier to write with precision that a more unrestrained one. In any case, it had more experience with the former to hone his craft.