Powdered meal replacement vs regular meal
Yes you could live off a protein shake type supplement if it had the vitamins, minerals, protein, carbohydrates, and fats you would need. Would you want to? Probably not. 

First thing we must determine is the protein whey or soy? If a male is consuming this meal replacement and the only protein is from soy, their estrogen levels will be elevated. In Soy Protein Isolate Increases Urinary Estrogens and the Ratio of 2:16α-Hydroxyestrone in Men at High Risk of Prostate Cancer, Dr.s Jill M. Hamilton-Reeves, Salome A. Rebello, William Thomas, Joel W. Slaton, and Mindy S. Kurzer concluded that soy does elevated estrogen in men which helped with the reduction of prostate cancer [1], but as a male, you wouldn't want to have a lifetime of increased estrogen [2].


Infertility. Estrogen is partly responsible for creating healthy
sperm. When estrogen levels are high, sperm levels in semen may fall.
This can lead to fertility issues.
Gynecomastia. Estrogen may stimulate breast tissue growth. Men with
too much estrogen may start developing larger breasts.
Erectile dysfunction. A balance of both testosterone and estrogen is
important for healthy sexual growth and development. Sexual function
may be impacted when these hormones become imbalanced. Men with high
levels of estrogen may have difficulty getting or maintaining an
erection.


So to be on the safe side, let's assume that the protein is from whey and we have one less thing to worry about. Now as for the vitamins and minerals, the Mayo Clinic states that [3]:


  Supplements aren't intended to be a food substitute because they can't replicate all of the nutrients and benefits of whole foods, such as fruits and vegetables.


and there are three main differences:


Greater nutrition. Whole foods are complex, containing a variety of
the micronutrients your body needs — not just one. An orange, for
example, provides vitamin C plus some beta carotene, calcium and
other nutrients. It's likely these compounds work together to produce
their beneficial effect.
Essential fiber. Whole foods, such as whole grains, fruits,
vegetables and legumes, provide dietary fiber. Most high-fiber foods
are also packed with other essential nutrients. Fiber, as part of a
healthy diet, can help prevent certain diseases, such as type 2
diabetes and heart disease, and it can also help manage constipation.
Protective substances. Whole foods contain other substances important
for good health. Fruits and vegetables, for example, contain
naturally occurring substances called phytochemicals, which may help
protect you against cancer, heart disease, diabetes and high blood
pressure. Many are also good sources of antioxidants — substances
that slow down oxidation, a natural process that leads to cell and
tissue damage.


So you could live off of some meal replacement shake for the rest of your life but should you? Probably not.