Public companies sell products that people actually pay money to use.
You can literally look at the Top line audited Revenue.
Can companies be overvalued? absolutely, just like how it can be massively undervalued (e.g META)
crypto, gold, art are asset classes that don't produce anything. So, you have to find other suckers to pay higher. But all three is based on scarcity. So, it is a supply/demand philosophy (vs cash generating assets like Bonds, Stocks, Real Estate). At least BTC/ETH/Art/Gold has natural supply limits, so the only unknown is demand. How do you induce demand? By telling stories about the asset class.
Art lends itself to natural storytellling. What about Gold and Bitcoin? The charlatans and hucksters and persuaders quickly figured out that "hating government" is universal and scales very easily. So peddling Gold/Silver became easy in the name of government and Gold performed the role of this anti-government asset class for quite a long period.
The initial internet adapters, Gen-Xers also leveraged internet (zerohedge, infowars, dredge report) to amplify anti-government/elite hate and peddle gold. This worked pretty much till 2012.
But, 2012 onwards Millennials started to take control of the internet narrative and buying Gold wasn't easy on the internet. So, they latched on to this new anti-government asset class, BTC.
The era of influencers and social media accelerated Crypto story-telling culminating in peak viral story telling in 2020/21 due to the pandemic (combined with unprecedented free money both for the rich and poor).
Cryptocurrencies are here to stay, thanks to it scalable narrative about anti-government with 8 Billion Total Addressable Market.
However, BTC maximalists should be wary about BTC as the one-true asset class. As wealth concentrates among the 0.1% of BTC holders, and poor environmental impact story around BTC, newer generation may revolt and rally around another poor-man cryptocurrency (like Dogecoin or something else).