On the other hand, you can predict with a reasonable degree of accuracy that in three months, the price of the stock will be higher if the underlying market conditions don't change.
In fact it's the opposite. The larger the timeframe, the more unknowns there are. It's simply based on logic, as time passes, more new information comes about and other old information loses significance. So your 3 month old analysis can often be completely outdated and therefore useless.
Price action (and thus even indicators!) depict the psychology of participants and without any important news event or manipulator, that will determine what an instrument does in the next 10 minutes.
But we are in a massive bull market and I'll take a wild guess that you're either all long or mostly long. So you could be buying randomly and making money in any 3 months window.