The frame is that enterprise solutions for these problems do not scale to smaller retail chains, and I find that at least believable.
The thing about this problem is that it's not hidden. It's extremely obvious. I work in SaaS targeting logistics (transportation for me, transportation, order management and warehouse management for our company), so I know a bit about this space, though I'm not in it directly. Plenty of people are solving this problem for bigger companies.
I put roughly 0% credence in the idea that many many people haven't noticed this is a problem for smaller companies. I put low credence on the idea that no one has tried to solve it for them via software. What I suspect is that this is a case where the basic idea is super-simple and obvious, but the reality of producing something that works in the market is hard.
None of that is to say that there couldn't be a real improvement here. It's just that I suspect it takes a real insight into why this problem hasn't been solved yet, and a new angle to make your solution work.