There isn't a one stratefy to rule them all. If you want to be profitable you always have to adapt according to the market conditions!
but there are also times when old strategies work again, although at some point you'll have to revise your strategy again while adding the newer ones. as you've have said that it depends on the market conditions, and i still believe that some old patterns are still useful in todays trading style. still for one to become a seasoned trader, you still need to experience more trading patterns or should i say it is the culmination of your accumulated experience in trading.
The moment a strategy fail, it can only say of the fact that it's bad, no good strategy for trading will fail now or later. Another good thing about good strategy is that it works with all asset you trade them with, it will never be selective. The success rate of different asset can differ, it will manage to deliver a good result. To get such good strategy may take time, it takes reading, learning and practices for years. More so, the strategy has to be simple and trade the direction of the trend, not the kind that will look like too perfect to trade the direction and the opposite.