They are not on the hot news now but it doesn't mean they are failure, it is just there are some new projects that are new to some people and of course they are much more interested to it.
Privacy coins might not disappear, but they'll be out of the spotlight as other cryptocurrencies gain the attention in the mainstream world. Cryptocurrencies with built-in privacy features will only represent a small portion of the market, as Bitcoin and smart contract platforms like Ethereum, Solana, and Binance Chain take the world by storm.
I'm hoping people will turn to privacy coins the more invasive government surveillance becomes in the future. Monero is the leading privacy coin on the market, so I'm guessing it'll gain the most traction after this. Centralized exchanges might de-list privacy coins, but people can still use decentralized exchanges or even atomic swaps to get access to them. I'm fine with that as long as everything remains decentralized. Just my thoughts