You are expecting your stepmom to take your side. Please, if you value the relationship, do not put her in that position. She married him, she did not marry you. While it would be nice to have her support, you chose to cut your dad off.
She is not calling or visiting because she is being respectful and following your cues, the ones you have made clear to one and all.
You seem to have a lot of posts about other people's actions and how you interpret them. You don't seem settled or happy in any of your relationships. Maybe some counseling might be helpful so that you can find your own path and see what parts of your life *you* want to work on. We really have to let go of our expectations of others to validate us or make us feel contented, happy or secure.
And your question at the end-- what would I do? Sit and wait. You made your bed with your dad, you have to lie in it for a while. Telling her "about how she has made no effort to have a relationship with us" would be manipulative and cruel. She owes you nothing. You put your 'being right' in front of your relationships, and put her into a situation I'm certain most people would rather not be in. She's supposed to reach out to you and come see you because you won't see your dad and you think you are 'right'?, so he can know he's wrong? It leaves one a bit incredulous. You really need to look at your own behavior and what you expect of people, because even in my long-term relationship with my stepmom (over 31 years), I would never expect her to throw my dad under the bus during a dispute and come take care of my feelings. I respect them both --and their marriage--*way too much* to expect that of her. Start with you, first.
ETA: lest one feels I do not have compassion or empathy for the situation, I have been estranged from my own mother since 2001. No contact. I did not expect my sibs or grandmother to 'take my side', nor have I ever contacted them with any expectations in that regard. It would put them in a terrible position. They have come to their own conclusions in regard to her; I had to just sit with my decision to go no-contact and own it and not put them in the middle. It's hard to lose people in one's life, but if it means peace, then you accept that there is sometimes a price we pay for that, especially in a dysfunctional family. I've walked this path for 15 years now. I've let go of a lot of unrealistic expectations of people. It's made the relationships I do have with other family members so much better.