It's one of the truisms of life that the business case for saving humanity from Armageddon is generally void. Any money spent on avoiding destruction of the human race is wasdted if the effort fails, and if it survives, then unless there's a 'hook" that benefits this specific investor, then the money is also wasted - it merely allows "business as jormal" and the company logically should ignore the opportunity and just focus on business as usual, anyway.

Making business cases for things only makes sense in a business context, imho.

The case for expansion of the human sphere or survival of the human race needs to be made on other grounds.

You might compare Columbus' business case for discovering the New World. He didn't intend to discover it - in fact it was in the way of his plan to find an easy route to the far east for trade - and THAT was the business case argued with Queen Isabella.

In the same way, the survival of the human race in the space era is likely to be "bought" as a side deal or accidentally when some other more commercial transaction is made - like developing asteroidal resources leading incidentally to a space-faring population and off-Earth habitats.