Well, the market did go the other way around for a very long time. Almost the entire year in 2017 crypto was going up and up in price. But what people buy, people also sell.
And with all the hundreds of tokens coming out, people HAD to buy them, or invest in their ICOs. This was done with big coins like ETH and BTC. So, it makes sense that those coins eventually lost "value" as people were essentially selling them to get ERC20 tokens.
In other words, one of their options to stop the market decline, you need to stop the emergence of new altcoins?