a) Ampha does not come on the market then Sandoz will remain near 50% market share - because two players can tacitly settle on a fair market share via signaling etc.
I don't get this assumption. Aren't you saying S/A won't sell ANY generic? Isn't their goal to get a fair share (50%?) of the gerenic market? With little difference in price, that would give them 75% of the entire market. Maybe they keep the price the same in order to keep the Lov 50%. If price starts to go down, they have shot themselves in the foot overall, but not they are still better off than not having a AG.