Physics has to have always existed.
Not necessarily. The rules that allow this universe may very well be able to arise from nothing, or they could have existed forever. As far as I know, there isn't enough data to conclude either position, although I'd love to be proven wrong on that!
Maybe our ability to understand true reality is closer to that of an amoeba than we think. Physics postulates more dimensions than we can perceive. We see a tiny part of the electromatic spectrum.
There will always be things we don't know and we aren't capable of perceiving. I sit here with ancient fillings in my teeth, I'm sure my head would look like a strobe light to a creature that can see the full spectrum of light with all the radio waves, microwaves and such hitting me right now. You can't know reality you can't perceive. Reality is, the concept of I don't understand but there must be an explanation that I can understand is not true. Questions you can't answer, you can't answer. Religious people fill in the blank with God did it. Just let go of the question until you have enough information to formulate an answer.
I dunno about your time line, man. Given the exponential rate of knowledge growth, when not held back by a fundamentalist religion ... 500 years is a damned long time to say we'll learn almost nothing.
I'd also disagree that we're no closer to knowing anything than we were 100 years ago. In 1910 1911 (god dammit) we didn't even have a good model for DNA. We also didn't have a hadron collider.
Here is a thought I had about it, it seems like we are still stuck in the mindset that what we can perceive is all about us. Like it's our universe and everything else is nothingness. Wonder if there are just as many universes as there are stars in our galaxy or more. We should not discount the thought of there being a "big bang" happening right now somewhere and creating another universe amongst a sea of universes. Imagine our neighboring universe being so far away that we never develop the technology to ever detect it. This idea expands my thoughts on the definition of a "universe". We might would even need to come up with a new word for a network of galaxies rather than "universe" if the universe made up of other networks of galaxies that are separate from our own. If matter has an infinite past then it is possible that space and other possible galaxies can go on infinitely also. Please understand that I am not saying that this is the case, I only toy with the thought of it being a possibility.
Also, when asked where did the universe come from I retort with why did God make everything? At some point he/she was satisfied with nothingness and became bored, or unhappy with it. His needs or wants changed at that time. Since then it has been 13 billion years, plenty of time to change his mind again. Wonder if he got bored again and went on to create another dimension of reality that we have no part of.
nothing isnt nothing anymore!
Dr. Krauss at AAI 2009