Is Staking profitable? In one word, yes. Staking is nearly as profitable as the mining or trading of cryptocurrencies, and without risk. All you have to do is stake (buy & hold) some coins in order to get added to the mining pool.
This is not perfectly correct. For example, you stake Coin A, with 10% annual interest rate, but Coin A price during the period fall and depreciate down the price of your stake over 2x. In this regard, you staked Coin A, but is the stake profitable? Absolutely no.
Staking profitability depends on the price of the coin when you staked and the price during the time you are removing the coin from staking.
It is very possible that the coin you have staked in the past were profitable for you, but this does not guarantee that all coins staked will be profitable, if the price of the coin staked falled lower than the price you staked it to the extent the fall is beyond the annual profit, then that is a loss.