Oh, no. *not* due to strikes. It is greed, pure and simple.
Seems they released some movies and found they made 15% less than projections because the stars weren't going on talk shows and radio to promote the release. So - rather than lose money, they pushed out the release until after they hope the strike is over so they can get the actors to do that promotion. The vast majority of actors won't see dime one if that extra 15% their promotion earns, and none of the crew will - but they all suffer.
The studios seriously need an attitude adjustment.