Amphetamine allowed me to write this... You may find it enlightening; although it is not comprehensive regarding the distinction between metaphysics and modern physics, I do go in depth explaining their relation to one another:
You could perhaps view metaphysics as the predecessor of theoretical physics (not just quantum physics), since metaphysics sought to answer questions regarding the inherent nature and origins of the universe, but not through scientific experimentation.
Metaphysics was more prevalent in before the 20th century - an explanation as to why philosophers were attempting to solve such problems and not scientists is because there was no equipment back then for testing the hypotheses of such subjects. Hence, metaphysics was mostly a guessing game - using dichotomy to construct a very crude epistemology with logic alone as the tool for crafting it.
Also, the line between "science", "philosophy", and "religion" becomes more and more vague the further you go back in history. The cosmogony and pagan religion of some early Egyptian nations (for example, the Ogdoad) could actually be better defined as an early science rather than a religion, one which hypothesized the origins of the universe - producing an explanation that is not too far removed from modern theoretical physics (if we consider the context of ancient Egypt).
Thus, Nietzsche (having noted this intrinsic link between science and religion) said something along the lines of "our new contemporary science is not replacing the ascetic ideal, it is simply the latest, purest, and most noble form of it. Can you grasp that?" People often misinterpret this as Nietzsche calling science a new religion, when actually Nietzsche was simply pointing out that religion was the science of the past. Our current understanding of physics is nothing more than the latest paradigm of a long series of paradigms comprised of what we now consider "Ancient religions", "occult", "pagan", "alchemy", etc. New editions of the human species' collective scientific paradigm are more or less complex based solely on a reflection of that civilization/era's technology.
I would like to note one event in history that may serve as a good example: the arrival of the Spanish in South America and their discovery of the Coca Plant. The indigenous people's of the region told the Spanish that chewing the coca leaf would energize and empower the individual, and that the plant also had healing and medicinal properties. At first the Spanish didn't believe them and thought that chewing the coca leaf was just some demonic pagan ritual performed by the tribe. Of course later on, the Spanish did in fact discover the stimulating effects of the coca leaf, followed by the Spanish subsequently harvesting it and taxing it. The point being that the current scientific paradigm will dismiss the science they don't understand of older or less technologically advanced paradigms as being of supernatural, superstitious, or "evil" origins. A frightening conclusion being that many ancient superstitions, beliefs, and practices all had practical application - even those as bizarre as mummification, cannibalism, worshipping of leaders as gods, and human sacrifice; most of which had some sort of relevance to the evolutionary process of sexual selection (a knowledge of which has long since been forbidden by Judaistic religions, and ultimately forgotten).
I think we could now perhaps appreciate a concept fictionally presented in the movie "The Lawnmower Man" - "I've been realizing that nothing we're doing is new. We aren't tapping into new areas of the brain, we are simply awakening the most ancient".
Perhaps I have digressed slightly from the original topic of metaphysics and theoretical physics, but all of what I have just discussed is essential for an in-depth analysis of the differences between metaphysics and theoretical physics.
Just as the Ancient Egyptian Ogdoad had hypothesized the universe origin's necessitating elements such as "chaos" or asymmetry in the initial dynamic conditions, so does modern physics hypothesize the necessity for "asymmetry" to be an element of the universes origins, with concepts like "Uncertainty", the "Higg's mechanism", among others.
The ancient egyptians theorized that the creation of our universe could only result from the destruction of a previous universe - thus, this eternal recurrence causes all possibilities to be juxtaposed within an entity the Egyptians of Ancient Hermopolis called "Nun" (represented as a goddess, depicting her as a "watery abyss" with the element of water symbolizing the containment of "all possibility", a metaphor which was also used by the early Greek scientist/alchemist Thales). This almost precisely parallels "M-theory" in modern physics, as well as other theories in modern physics which incorporate concepts such as a "10th dimensional point of singularity".
Do you find it convincing yet that our modern theoretical science is just another repeat in a long series of repeats - just another Egyptian Ogdoad? The paradigm regarding our universe's physical origins is perhaps the most elusive and resilient to change over time - possibly because we had correctly interpreted it thousands of years ago, and the words used to represent it merely change to accommodate for the current era's technological capacity.
The outline of theoretical physics has long been already painted - we now merely have the technology to discover the underlying formulas so we can give theoretical physics a practical application. Fusion reactors, cancer therapy, and potentially the possibility of inter-stellar space travel are some of these "practical applications" our application of technology to theoretical physics will give us.
We have been building up like an ant-hive, with no real idea of what we've been building up to or why, but going forward none-the-less due to the lack of an alternative. We are just building up to the next step, whatever it might be, the next major shift in our species' paradigm. The core essential concepts (such as metaphysics) stay the same in the human psyche throughout the generations, stored within our collective unconscious - our DNA, being withdrawn and utilized as tools when they are needed. We are eternal (one way or another no matter what belief system you hold, they all show that human life is inherent in the structure of existence itself), with this world and our memories of it just being temporary play-time in a sandbox.