Crap altcoins will continue to exist because someone out there will always buy and sell or use them. Bitcoin's only relation to these altcoins is that the purchase of the latter needs the former because fiat is not the trading pair for each or them.
No crypto can be literally "destroyed" it is more like being "abandoned" and nobody is using it anymore. While new ones will continue to flood the market I doubt their number will reduce anytime soon. Because of the "get-rich-quick" screaming appearance of most of these altcoins at the start, the new investors will always buy them instead of going for bitcoin.
My view on bitcoin is that it is always profitable if bought at the low price. No such thing as dividend period or stable period here. Been watching for several years now and I know that the cycles continue if you watch closely.
No one can destroy altcoins, even with bitcoin, and the demand for altcoins will never go away, as long as people enter the market for profit and get rich quickly then altcoins will still survive.
I disagree, investors can destroy altcoins. If they stop patronizing new releases of tokens and coins, if they divert their investment to Bitcoin and other stuff, if they pull out their money on the altcoin market, and if people stop supporting altcoins, it can destroy the altcoin market. Altcoin market thrives because there is a continues to demand for it. If the demand is stopped, no matter how continuously the market is supplied with projects and new altcoin, the market will become idle and eventually destroyed.
The only thing that can hold back altcoins might be government regulations, but if there are such regulations, investors like us will be in trouble even if we invest in bitcoin. Many people expect altcoins to die because they are so full of scams and trash, but I don't want that because if it's only bitcoin, it can't be called a market.
Government regulation can slow down the progress but it will not entirely hold back any altcoin market as long as the demand keeps flowing. To be able to destroy a market, the demand should be eliminated first.