Just look at the suppliers working on the SLS SRBs and those working on the LGM-35 program, perhaps then you'll see the extent of the overlap. Furthermore, you might want to look into why the space shuttle had the architecture it did, and why space shuttle SRBs were being shipped out of Utah. Large scale SRB manufacturing has been, and continues to be, an enormous problem for the DoD. Hence why wasteful programs like SLS exist.
I suspect the facilities working on SLS solid rocket boosters are owned by Northrop Grumman, just like the companies that were left over from making Peacekeeper missiles, now making Sentinel missiles, are probably now owned by Northrop Grumman. This doesn't show that Sentinel - or any other program - is benefitting from SLS's supply chains in a meaningful way. It's hard to see how that's possible, given SLS's low-volume nature. But I guess I'll try to keep an open mind...
> Furthermore, you might want to look into why the space shuttle had the architecture it did
I have lots of opinions about that, but if you have some reference material you'd like to recommend, please do! (and if they support the notion that SLS SRB production is somehow a boon to SRB makers everywhere, I guess I'd be intrigued by that as well)