Doesn't that assume the market is perfectly able to assess value?
As an example the market decided Netflix was a terrible value when they announced they were a video streaming company in like 2008ish losing around half their value. Except we all know now that was not a priced in moment.
The market is clearly not efficient, otherwise there would be no opportunity for alpha.
You can go onto the market today and buy like-kind stocks at double digit discounts to valuation just because they're smaller cap/lesser known. e.g. Retail REITs, where the business and risks are almost identical.
EMH as commonly interpreted is clearly wrong in my view.
What is true is that the majority of people can't beat the market picking stocks, but that doesn't mean there aren't observable inefficiencies. Just that most people don't care or know how to observe them
As an example the market decided Netflix was a terrible value when they announced they were a video streaming company in like 2008ish losing around half their value. Except we all know now that was not a priced in moment.