There are mathematical certainties. In this instance we have that all exponentially growing bubbles will necessarily display the property that values grow and at an increasing rate just before the bubble bursts. This is so fundamental that I can't believe you don't see it. You can construct the growth curve out of this very fact alone. Therefore, the simple fact of growing values and increasing rates of growth in values is not determining bubble/non-bubble.

In other words, the statement "I know I am not chasing a bubble because valuations are high and growing at an increasing rate" is categorically false because this property is a common indicator of the exact opposite; that you are in an exponentially growing bubble.