The market is saturated. Exchanges can't rely on organic growth anymore, so they are manufacturing volatility in niche sectors to keep us trading.
Not only exchanges but even whale traders pump some coins in order to trap newbie traders who get excited to see low marketcap coins getting pumped and put most of their money in such coins. Once the newbie traders put much money in those coins the whale investors and even sometimes exchanges dump the coins that they bought at low value and take the profit. It's a type of rug pull but in a legal way.
Not only traders, but well-known personalities, like Trump and recently, and I don't know if you are aware, you can read it here,
Former New York City Mayor Eric Adams is facing scrutiny from crypto traders after a memecoin he promoted appeared to suffer a sharp liquidity withdrawal shortly after launch.
https://finance.yahoo.com/news/former-bitcoin-mayor-eric-adams-052728722.htmlSo it is still cluster f**k and we don't know what will happen on a project that we invest, and overnight it could literally go to 0. And if I remember in the bull run of 2017, it seems what the OP describe as "flavor of the month" attack did happened. And if my memory serves me right, that time there will be certain coins that will be selected to be pump hard and everyone making money like in a wild wild west scenario. I think what the OP describes here could have been happening in the past already but we just didn't look at it very closely as everyone is enjoying the hype of 2017.