Infinite money doesn’t translate into infinite R&D, unfortunately. As pointed out by books like The Mythical Man Month, you can’t necessarily speed up development by adding more engineers/resources.

Put another way, infinite R&D will produce diminishing returns very quickly in the same time frame with the same constraints. R&D is a very long game to play, and depends on anticipating and adapting to more favorable constraints.

Edit: that said! The benefit of investing in it anyway is potentially changing the course or severity if those constraints by having more control over them.