Technically, it can't be called a stranglehold yet. This would be Zakharova's fourth appearance out of 16 broadcasts, the fifth if you add the Bolshoi re-opening gala. Maria Alexandrova and Nina Kaptsova have had more broadcasts.
That Zakharova's broadcasts tend to be fast-tracked for DVD release while more interesting performances are left waiting is another matter.
Maybe you can help me sort out the Bolshoi offerings.
I am unaware of much for Kaptsova
Here is my list (not in chronological order)
1. Flames of Paria - Osipova
2. Nutcracker - Kaptsova
3. Giselle, class Concert - Lunkina
4. Coppelia - Osipova
5. Don Quixote - Osipova
6. Esmeralda - Alexandrova
7. Swan Lake - Alexandrova
8. Raymonda - Alexandrova
9. Bayadere - Zakharova
10. Sleeping Beauty - Zakharova
11. Bright Stream - Lunkina, Alexandrova (only ballet on list which I feel 2 ballerinas can be counted as stars)
12. La sylphide - Krysanova
13. Corsaire - Lunkina
14. Pharaoh's Daughter - Zakharova
15. Romeo & Juliet - Nikulina
Based on this list, here is the order of performances
4 - Alexandrova
3 - Osipova, Zakharova, Lunkina
2 - none
1 - Kaptsova, Krysanova, Nikulina
This adds up to 16 out of 15 offerings, since Bright Stream has 2 ballerinas
Osipova was running away from everyone before she departed, with possibly 3 of the first 5 or 6 offerings.