Nzx full year results, page-152

To value a company at 40 times today's earnings it has to have the potential of growth at the rate of 30 to 40% per year for next 7 to 10 years.

I think you're underestimating the power of compound growth

30% for 7 years gives growth of 530%, which would mean a P/E of ~6 (and that's the lowest of your example. 40% for 7 years, or 30% for 9 gives growth of ~900% and a P/E under 4). Assuming a terminal zero growth and P/E of 15 you'd get a return of 13% per annum on your company currently at a P/E of 40.

A company currently at 40x growing at 15% a year would get to a P/E of 15 in seven years (i.e. zero share price growth assuming no future earnings growth and a final P/E of 15). At that price you'd probably be looking for around 20% growth in revenue, that would give you a P/E of 11 in 7 years.