There's three ways to look at this scenario.
1. Marvel/Hasbro wanted to sit back and see how the consumers responded to the "Retro" style of the figures before pursuing their own 8-inch line.
2. Marvel/Hasbro wanted to see how their summer movies and all of the tie-in toys did first before looking to branch out. There is a great deal of money invested in movie figures.
3. Marvel/hasbro has absolutely no interest in this.
Hasbro is the king of 3 3/4 figures and may not deviate from that formula. It would be a severe financial risk to commit to a 1/9 scale line of figures. Mattel really jumped on the retro aspect of the figures to appeal to collectors. I think if Hasbro were to go for this concept, the focus would be playability versus nostalgia.
But, this is all hypothetical. If Hasbro had any intentions at all they would have jumped in by now. Or maybe it's an upcoming SDCC announcement...
India recently declared dolphins to be non-human persons and deserving of specific rights. Next, they'll try to do the same thing for women.