Is it really so bad if the apothecary-herbalist doesn't look for any herbs himself?
I use this building in dense building areas, so that the people don't have to walk the long way out in the woods to see the herbalist. So he doesn't find many herbs anyway. I would find it a big improvement, if the apothecary could store herbs. It doesn't matter, that the herbalist in it doesn't collect them himself. Build an original one out in the woods for collecting, or buy the herbs.
The idea of letting herbs be stored in the fruit market is bad! sorry! Think of the consequences: If you have a larger map, you have several fruit markets. Unless you have an awful lot of herbs, they will be put in one or a few of them and stay there (vendors don't steal from each other, remember?) and many people have to walk far to get their herbs, and then maybe another long walk to the herbalist to be healed.