Unlikely to happen and why would you need to? It's a train sim not a tourism simulator. And let's face it, DTG couldn't even be bothered to fully model Cardiff Central station on its route, let alone a factory/tour some distance from the station at Bournville.
I think that idea is likely to go down about as well with many of the folks on this forum as the vomilicious taste of modern cadbury chocolate...
The other problem then becomes that if they did that (they won't), they'll be people expecting more areas like it on every single release
