Shooting isn't over yet for most of the films. Until the shooting is complete, or close to completion, they wouldn't sell the streaming rights to any OTT platform.
Films like Bhool Bhulaiyaa 2, Hungama 2, Attack, Satyameva Jayate 2 aren't complete. That's why they aren't releasing.
I dont think we will see any new Bollywood content on Prime, Netflix have already released their biggest movie in Gunjan Saxena. Maybe Ludo is another movie people might watch. Remaining 14-15 films are duds.
Hotstar still has it's trump cards left which should release in September. And with the IPL coming up around the same time, there will be a huge increase in subscription.
So only the Hotstar movies are left to release, unless there are new contracts made once shooting of the remaining films are complete.