This explains why some investors take the risk. When such a technology does succeed, it brings a large financial benefit that makes the risk worthwhile.

This does not explain why people invest in those technologies. It states that such technologies are numerous, not that they are generally successful.

This does not state that most investments are risky, but rather identifies a new category of risky investments. Simply the existence of this category does not explain why the technologies in question attract investments.

It is not stated whether the technologies in question fit this description. It is possible that no technologies that promise to extend life and decrease pain seem likely to provide a large financial return.

This is irrelevant information. No relationship between the understanding of the natural world gained from research and the tendency of people to invest in that research is implied.