At operating cost of $3,264/tonne IPT will be the lowest cost...

At operating cost of $3,264/tonne IPT will be the lowest cost producer in the world of HPA. Its recently released MRE indicates a mine life of 75 years at a production rate of 10,000 tonnes pa and the resource is likely to be increased, as not all the lakes have been explored in IPT's tenements.
Once in production it will become a dominate market player and many other HPA producers like A4N will see it as a threat, as it will be able to double or triple production quite easily and cost effectively.
You are right that there is no guarantee that those demand forecasts will be met by 2030 and does vary from different sources. But IPT will be able to weather the ups and downs of the market being the lowest cost producers, even at 1000 tonnes pa it will still be profitable. When there is the demand, ITP will be able to double or triple its forecast production of 10,000 tonnes pa quite easily.
IMO one thing for sure is that demand for HPA is to grow exponentially on the back of the growth of the electric car market and LED light market growth. Every new car battery will require HPA and every new house or apartment building will require HPA for their LED light fixtures. Even every mobile phone and TV requires some HPA.
More than one in three new vehicles sold in 2030 will be electric thanks to “explosive” growth in the market, according to the International Energy Agency (IEA).

From the Scoping study on future HPA demand growth, which I believe is on he conservative side:

Another source for HPA growth in demand in the US market.

They both show very strong growth in the coming years.

Growth in electric car sales: