Oscar McInerney has less risk than Marshall.
The risk that is facing McInerney is the unkown risk of Fort affecting his SC scoring. Besides this unknown risk, I can't see another risk to McInerney. Marshall has the injury risk and Ryder.
The extremes with Fort is, he doesn't play at all, or he takes 50% of McInerney's ruck work. I think it is somewhere in between, with McInerney doing the majority of the ruck work. McInerney proved, end of last year, that he could ruck for most of the game alone, but that is not sustainable for the long run, so he needs to be managed and that is where Fort comes in.
Looking at scores after the Byes, McInerney had a slightly better floor than Marshall.
When it comes to fitness and staying on the park, McInernery is well ahead.
Even value wise, McInerney is $27k cheaper.
I just feel that I am missing something, as to why McInerney is not more popular with the SuperCoaches.