If I had a few hundred billion lying around, I'd be spending a couple of billion a year on grants for new physics research.

Hire all those smart people who waste their lives being quants and steer them in the direction of something useful.

This is fair but I'm not sure the low hanging fruit is going to be developing technology that can reach earth escape velocity without being extremely sensitive to how well built and prepared the system applying the enormous amount force required is. Even the hypothetical stuff like Spin Launch and space elevators is going to have catastrophic failure modes....

> If I had a few hundred billion lying around, I'd be spending a couple of billion a year on grants for new physics research.

Unfortunately, this is not the way the world is going right now.

Physics research, and generally speaking fundamental research, is publicly funded.

Meaning, most of the time, under funded.