To grab a large slice of some niche, you need to be invested in exploiting it. In Kodak's case, that meant having all these huge facilities for film technology. There's no other way to be a big player in this niche. The upside is nobody will ever avoid thinking of your brand when they are shopping for film.
The downside is you can't just change direction. If film becomes obsolete, the market in the replacement is not going to be big enough at the stage when you can see it. And its size is in itself what you will be using to judge whether it will happen, so it's quite hard to decide to dump all the old tech in favour of a tiny industry that might run into trouble. I'm sure there were many naysayers pointing out various flaws and potential roadblocks with digital.
If you do change direction, you inevitable step on the toes of someone else in the value chain. You make your own camera, you annoy the camera manufacturers. You want to be a chemicals business? It's full here, too. Remember you're a huge operation, and there's only so many things to do.
We should not mourn the death of large corporations though. Just like in nature, it frees up resources for new players doing new things.