I am pretty sure a GM also calls the shots on all the trades made and players added. I don't think Hart would've let Shapiro take the phones and wheel and deal (which I doubt that would happen anyway since Shapiro seems scared to add anything.)
I am gonna keep going about Shapiro...He might be respected like you said before, probably because he is a nice guy, and thats it. He has barely grown any type of talent through the draft and does not seem very aggressive when it comes to adding pieces to help contend. In what way has he been a great executive? He seems to be more focused on hot dog combos and transportation for the fans than anything.
He has lived off the trade of Bartolo Colon his entire career, and has nothing else great to add to his record. He failed to add anything significant in the offseason when the team comes off a promising year. He failed to bring in any effective prospects for 2 Cy Young winners. And year after year he takes marginal players in the draft so they can "save money for later rounds"...who in the later rounds is worth saving money for??
And yes, he brought in the likes of Asdrubal Cabrera, Shin-Soo Choo, and a few others for nobodies...thats great, but he has failed to surround the talent he has brought in.
And don't even say he isn't involved in player movement as much since Antonetti is the GM...we all know Shapiro is breathing down his neck.