This is a bubble which will not burst because we are speaking of Google. If (theoretical) Google will be valued by it's real profits and downgraded by ads profi

This is a bubble which will not burst because we are speaking of Google. If (theoretical) Google will be valued by it's real profits and downgraded by ads profit the WHOLE online ad industry will go bankrupt. But this is really unlikely because ads pricing is not the same as stocks on an a stock exchange.