Something is a bubble if its future discounted cash flows cannot cover its current valuation. Can the author please make a rigorous case by looking at actual nu

Something is a bubble if its future discounted cash flows cannot cover its current valuation. Can the author please make a rigorous case by looking at actual numbers (e.g. her predicted valuation 5-10 years ago vs now.. or analyze a few companies today). Or can she please refrain from writing such general, alarmist and meaningless articles?