People are using the knowledge they have today to explain what was "obvious" in the last bear market, and are using this to predict the future. That's stupid.

Earlier, I saw a post saying something along the lines of "don't be stupid and gamble into altcoins, only buy BTC and ETH. If you had done that the last bear market and had bought ETH at $100, you would have made a fortune!". Similar posts are frequent.

However, they are also stupid, and are using knowledge we only have in hindsight for their reasoning. People who have gotten into crypto in the past few years might have the impression that ETH has "always" been the clear #2 to Bitcoin. I've even seen people seemingly under the impression it was the second crypto around. This is far from the truth, it was established in mid-2015 and is much younger than several other big coins, e.g. Litecoin (2011), XRP (2012) or Dogecoin (2013).

Until 2016, most people would have seen Litecoin or XRP as "obvious" #2 to BTC. While ETH took over that spot at some point in 2016, it was far from obvious, and other coins like BitShares and Bitcoin Cash came close to taking that spot at different points in time in 2016 and 2017. XRP even re-took that spot from ETH both in late 2017/early 2018 and in late 2018. ETH seems like it would have been an obvious choice to DCA into in retrospect - but back then this absolutely wasn't the case. When the bear market of 2018ff. started, ETH was an established altcoin, comparable to an established top 10 coin today, not more than that.

Long story short: the people telling you today you should only buy BTC and ETH and ignore altcoins pretend like it was obvious those two would come out on top after the last bear market. It was not. Last time, the same people, if they were around, might have told you to stick with BTC and XRP, the more established coins, as newer coins like ETH would die in a bear market for sure. We have no idea what will happen this time. Maybe BTC and ETH will remain dominant, maybe some other coin will take ETHs spot, hell, even if it seems unlikely, maybe at some place we will see a different coin at the top spot than BTC! I am definitely not telling you not to buy BTC and ETH, but those people pretending it is a law of nature they will always stay on top have no idea what they are talking about.