New coin is released, you want all hashing power you can get to mine in first days, looking at profit if it makes it to any exchange, would be one of my guesses.
That is correct.. Lets take an example from 42 which I mined only for few hours solo i had 24000 dents which i sold for around .45 BTC
you are always taking a risk when mining new coins. RPC/CAT paid of initially but on the other hand GFT,MOON,COYE,HOLYNOODLE etc failed but
soo... its a risk
If you know which coin to mine, you can make a real fortune. I mined 42 from the day it came out up to the day it hit cryptsy with my 5.5 MH/s. When it appeared on exchange and I saw a chance for price 400 BTC, I dumped all, which gave me 2.6 BTC (for ~5 days of mining - that is 0.5 BTC per day!). Unfortunately, I dumped too soo, if I had waited more time, I could have made 10+ BTC (2 BTC per day of mining!!!). This is just nice example that even with renting, it is possible to make loads of money, you just need to know what to mine and at what time.
I also earned nice amount on DOGE (4-5 BTC for few days of mining) and VEL (~3 BTC for few days of mining). There were other coins, but less profitable. Staying on multipools or simply mining regular established coins for low profit is waste of time in my opinion.