According to physics gravity should be a much stronger force. Here is an interesting explanation of why it might be weaker. Persons this theory might relate to MBT e.g. it might include different planes.
Or maybe there is some other reason that Tom has determined.
I have a better idea of what you mean now, this is from her Wikipedia
"[...] possible solutions to the hierarchy problem
concerning the relative weakness of gravity, [...]"
So it seems you are asking about the so called "hierarchy problem", which is according to the Wiki article: "In theoretical physics, the hierarchy problem is the large discrepancy between aspects of the weak force and gravity. There is no scientific consensus on why, for example, the weak force is 10^24 times stronger than gravity."
I'll read the wiki article, and post my thoughts later.