[Lotus]

"Why does breast growth fail/falter or disappear?....the reason (imo) is that it's lacking a vascular network, and without a current blood supply to new tissue (breast) disappears."  

Interesting.  However, I'm not entirely sold.  If this is the case, why do women who work out (especially if they lift) actually see a reduction in breast size?  

I doubt in that case breasts are to be the only area seeing a reduction of fat, meaning losing fat comes off all over. 

My point is breasts lose their integrity (cell shape and volume) for a number of reasons, I'm offering a supplemental theory. Maybe sustainable breast growth is a continuation of protein synthesis, which is the basic building blocks of DNA synthesis, here's some background on DNA.
https://www.ncbi.nlm.nih.gov/books/NBK22022/

My thought goes beyond protein synthesis though, meaning where and how is it activated in breasts?, the science is there tbh. One example is using the mTOR signaling pathway, and basically,   mTOR (also known as a kinase) can activate Growth Hormones which stimulates protein synthesis....or more specific....milk proteins.
http://physiologyonline.physiology.org/content/21/5/362

Bile-salt-stimulated lipase in human milk: evidence for its synthesis in the lactating mammary gland.
https://www.ncbi.nlm.nih.gov/pubmed/3595844

Getting back to why breast growth falls short...think about it, if adding fat / building muscle / more collagen deposits / growth hormone and a vascular network can grow bigger boobs...well, why the hell not?...

Ask yourself, when fat is transferred to augment breast size (aka liposuction for breasts) why does only a portion of fat take? (succeed), perhaps if the above concept was advanced prior to fat transfer then the transfer rate of fat could be higher?.....just a theory. Based on evidence that vascular aromatase is in smooth muscle tissue via ER-a (estrogen receptors alpha) we know it'll have a hormone source for continued growth rate ...it's just developing the vascular network. 

Quote: Muscle growth occurs whenever the rate of muscle protein synthesis is greater than the rate of muscle protein breakdown.
http://www.unm.edu/~lkravitz/Article%20f...rowLK.html

.....what if a happy equilibrium (or homeostasis) between muscle protein synthesis vs. muscle protein breakdown can be achieved?.....