The female breast contains BOTH gland tissue and fat tissue. Glandular breast tissue is more prevalent in the younger breast and its ratio to the amount of fat decreases with increasing age. Since Liposuction CANNOT remove breast gland tissue but only fat tissue, liposuction (IE vacuum) applied to the breast will remove a small component of large young breasts (which are mostly made up of gland tissue).
But, even IF all breasts were fatty and could be magically half-emptied with liposuction, the technique would be a poor way to reduce breasts. The mere emptying of a large bag of its contents does NOT make it perky nor change its appearance for the better. in such fatty breasts, all Liposuction could do is deflate the breasts and make them smaller and saggier. On the other hand, A Breast Reduction reshapes the breasts and makes them BOTH smaller and perkier.
Summary - Liposuction for Breast Reduction sucks... (sorry. Could not resist).