it's not hard to figure that out as 4 years ago the price was peanuts compared to now. no one knows if you buy now and hold your coins for 4 years that you will be guaranteed a profit. the chances of seeing the price go higher as we progress through the years are indeed high, but we can't look that far in the future. i never take things for granted in life. bitcoin is no exception.
That's true. Holding for 4 years seems silly if we consider the current price. 4 years back the price was quite cheap to buy and hold but now it's $540. Imagine if it would reach $100 or less, the user will lose $440 per bitcoin he holds.
It's not gold whose price keeps increasing or property as well. Bitcoins are dependent completely on the market and holding for a year is sensible. Not over a year.