There is an excellent article which I read which explains why odds are stacked against shorts in the long run. Shorting is always a short term play. I am going to try to find it.
hope you can find it, like to read it

I am not sure what the article says, but I can name 2 reasons:
- mathematics: in a short position you can only maximally make 100% of the money you put in (if you don't use leverage). If you short $100 worth of something, the best you can hope for is it goes to zero and you make $100. For longs, profit is potentially infinite. Ask somebody who put in $100 in bitcoin when it was worth $1/BTC how much money they made, it is slightly more than $100.
- inflation: In a world where fiat is the currency, and central banks have a mandate to produce 2% inflation, assets that break even on purchasing power go up in price 2% a year. That means that shorters lose 2% a year as a baseline. (shorting something denominated in bitcoin might be less unfavorable for this reason).
EDIT:
- a third reason: risk: a short position is always a margin position with risk of liquidation. Longs can just keep their position for years without ever having to worry about being wiped out due to market volatility.