1. You could discover a new theory every single day for the next trillion years, and there will be plenty left to discover. Physics is inexhaustible,
2. and any attempts to lay a finite TOE definition down will result in failure.
3. It's not just the TOE that is forced to these rules, but all these physical systems. So how
are you going to tie these systems together when you will never fully understand any system? You can't and that is why people like Stephen Hawking is coming across. You will never explain all of the fundamentals experiments with a TOE, ever.
1. True. There are plenty of things which are too difficult to derive directly from the first principles. Take organic chemistry for example.
2. False, if by TOE we mean "the most deep (fundamental) theory"
3. You logic is wrong.
Finite set of Peano axioms defines a world of number theory - you can study all the consequences of these few axioms for, as you say, trillions years.
You can explain the rules of Chess game on a small piece of paper, and it keeps so many people occupied for so many years.
If you remember, there is even simpler thing, the "LIFE" game on an infinite board, simple rules, infinity of possibilities.
So an infinite complexiness of our world can be a result of a small set of TOE equations.