The world isn't static, a "reliable" profit is worth less and less each year if a company isn't growing. Companies are valued based on their future earnings pot

The world isn't static, a "reliable" profit is worth less and less each year if a company isn't growing. Companies are valued based on their future earnings potential, growing companies will thus be valued much more highly. In Yahoo's case not only was there no growth, but their business was shrinking without a clear path to stopping that.