Bro... the author isn't discussing one stock, his article is about the entire stock market being overvalued. Whereas, in your comment, you're looking at an individual stock: TSLA. This is not a fair comparison.

Furthermore, the Buffet indicator doesn't have anything to do with the Buffet's performance vs S&P over the past years. The Buffet indicator is the ratio of stock market cap to GDP. It's an indicator that companies, at this moment in time, are selling shares at a price way more than the value they're producing.

Moreover, you're confusing speculated stock value, which doesn't have much relevance to the author's article. There's a big difference here that you're missing. Let's say there's a company XYZ that makes $1 in profit per share per year. Then, let's say the best bond available gives me a 1% APY. Then, it only makes sense for me to buy stock of XYZ at $100/share.

However, others might think that XYZ will revolutionize the car industry and they might think that in the future, XYZ will generate $100 in profit per share per year. They want to get in on it RIGHT NOW. This urgency in time creates a high demand for the stock, while the stock supply is fixed. This drives the stock prize up, purely based on hope that XYZ will achieve something. This is called speculation. It's called speculation because there are lots of 'what if's' and there is no analysis known that can predict this.

TSLA is great example of speculation. For years, Musk has been promising things that have not been delivered (full self-driving since ~2016, Tesla robo taxis, etc.). Yet, the mass still hopes and believes that he will deliver. This belief with FOMO raises the stock price. Remember the time frame of the urgency is important, because the demand has to be greater than the supply.

What the author is talking about has nothing to do with speculation. His article is about the present reality. The stock market is overvalued.