Who pumps GRS? What is the point to keep the coin does not bring the owner any income? Just wait for the pump and sell.

There are all types of "investors", and it all comes down to short term/ long term (your timeframe) and some of these are of course speculative traders, like you seem to be. I am one too sometimes. But I believe that there are much better instruments for that purpose, because mainly, what you need is BIG liquidity and daily movement (volatility), FOREX is my choice for that, but also some commodities are good.
I chose cryptocurrency and specially altcoins, for a long term investment, you can actually see big returns 200%,300,500. These numbers are very real, because it's the new thing, everyone is looking to jump on and have the fear to miss out, so hype is strong. That for me is a great way of buying cent coins and looking into 1-2 dollar marks.
So in response to you, you could consider foolish to not pump and dump alt coins, but I myself come from 6 years of investing in forex and thanks to big leverage and no need of big capital, you can be a intraday trader and pump and dump multiple times during the day, or even on 3 different market times, europe, US and Asian. I've done pretty well doing so, but it's quite stressing too. So for the purpose of investing, I believe that those of us who are here for that reason, wont be dissapointed, lose or win. But for someone who is looking for speculation and fast in & out operations, there are better instruments for that, I'm 100% sure. Just looking at the volumes you have on cryptocurrencies would be an absolute deal breaker for me, as a intraday or swingtrading speculator, so I don't really see your critic here, but I could very well see some strong down points on your gameplan here.
But anyway, who are we t judge what others decide to do with their money. What I do see wrong, in any way is to consider that investment should give you income. The word income has no place here I believe. These are investments, they should not be what is supposed to put food on my plate. Don't get me wrong, I do want to have return on my investment, but calling it income just sounds wrong.
Cheers!