Technically, the answer should be "no". Crypto going to $0 would mean that all money must flow out of crypto which would be pretty unlikely. Next there would be the issue that there are lots of lost wallets in many different projects, which would mean that all of those wallets would need to be found and emptied, which would honestly be really unlikely. Of course it could be possible to go to zero too if all exchanges were to close / shutdown, and any place that had a interest in crypto / bitcoin decided to value it at zero even with the locked wallets. I would still imagine that it would be extremely unlikely though.
With that being said though, if Bitcoin were to drop to say $500 or $1000 again, I would imagine that there would be a massive influx of buying pressure. That alone would keep it from getting close to zero imo.
I don't see Bitcoin replacing fiat anytime soon though. I think there's too many issues with that (especially the volatility).
Crypto has gone a long way since inception. Many businesses, corporations, and individuals alike are still supporting it today. Despite the recent "bloodbath" in price, crypto hasn't managed to go to zero in terms of price across the market. As you've said before, all the money from crypto must be drained on the market for prices to go to zero. That's very unlikely to happen in the future since there are still people who buy and "hodl" crypto. With an ever-growing number of use cases on the Blockchain, it's nearly impossible for the entire industry to head all the way to zero.
I believe that the only ones saying that "crypto will go to zero" are those who want to spread "FUD" more than anything else. Warren Buffet is very skeptical about crypto as he believes it's worthless. Yet, the space has proven him wrong as crypto has been booming ever since it came into inception in 2009. There are so many developers working hard in order to make the Blockchain a better place. Bitcoin, being the father of all cryptocurrencies in existence, has managed to perform well after all these years. It has never gone to zero in terms of price, despite its setbacks over time. The only cryptocurrencies that will go to zero are those which are widely abandoned by their developers with no real use cases for the mainstream world. The rest will continue to be actively used and supported by people worldwide for many generations.
Nonetheless, we all know that nothing lasts forever. Maybe something superior comes up in the future that will threaten the existence of crypto in the future? Or maybe all the governments of the world decide to crackdown on the space in its entirety? If any of these events happen in the future, you could expect prices to go to zero across the market. While Bitcoin and other cryptocurrencies will still be alive, they won't have market support. But the odds of this becoming a reality are 0 to 1. Just my opinion