Last time I checked, Litecoin is still at a block reward of 50 LTC per block. Sure difficulty has gone up and where I use to make almost 3500 LTC a day 2 years ago, today I make significantly less. So yeah, I've been around a while and have hardware to back it. BTC was just halved end of 2012 and that was what 3 years of mining with the same reward. Dogecoin I have my own opinion on why it will fail, but this isn't important in this thread.
I mined when the price was 0.00128 and it wasn't profitable then. Now the price means that mining was profitable. If you mine dark it's a longer game. And basically you mine because you can't afford to/don't want to buy. At least it can be mined with a lower power cost.
And actually.. I can get 0.5 LTC a day or 1 DRK now which works out pretty close in BTC value. Yes there are more profitable coins to mine but that depends if you want to dump them for BTC right away or as a longer term investment.