If you mean my deck. 4
![Light :light](https://elementscommunity.org/forum/Smileys/solosmileys/../../../images/Misc/light18x18.png)
from QP is a little costly early game and with the exception of black holes, the cards that Sanctuary blocks are not harmful mid-late game.
But the main reason is that the deck has too little offense, adding more Sanctuaries requires removing damaging/strategic cards. Mine is 40 cards too and it is already hard to find what you need, making it over 40 would make it too unreliable.
I have 2 versions and none wins by deckout. One has neurotoxin and the other quinted growing critters.