The biggest problem with Spinlaunch isn't the physics, it's the economics. The big complicated launcher, the acceleration hardened hardware and requirements for the payload to be similarly hardened, the mass penalties that result and mean the payload will be less functional for its mass, even ignoring the things it's just not feasible to harden for those launch stresses, the limited target orbits...all of this adds to costs and limits flexibility, with the explicit goal of reducing propellant requirements in exchange.

The problem: the total propellant cost for a Falcon 9 launch is around $200-300k. One Falcon 9 launch is equivalent to around 80 Spinlaunch launches in a direct mass comparison, likely double or triple that when you account for the mass penalties on the Spinlaunch side, so that's around $1-2k for a Spinlaunch-equivalent payload. The booster is bigger and more expensive, but hey, SpaceX reuses that part, and in fact burns extra propellant to do so. Spinlaunch is a fundamentally misguided attempt at optimizing something that's almost totally irrelevant. Yaney doesn't understand why launch is expensive, he hasn't bothered to learn anything about the subject, he's just convinced that his "vision" is enough. In space launch, it isn't.

Additionally, Spinlaunch requires a huge flight rate, they've spoken of launching over a dozen times a day. There simply aren't enough individual satellite launches to provide that kind of business, so it needs a Starlink-scale megaconstellation to keep it busy. However, such a customer won't see any benefit from Spinlaunch, they don't need individual launches to customized orbits on a short schedule, they need bulk deliveries of satellites to common orbits. They can get that more cheaply and faster with other launchers, and without having to harden thousands of satellites against the Spinlaunch launch accelerations.