“If one scientist hadn’t made a special discovery, surely another eventually would have made the same one.”

That is not sure by any stretch. The Germans put the first man made object into space in 1943 by launching a V-2 rocket straight up. When the war ended, the Allies had the remaining rockets, the plans for the rockets, and even the bomb damaged facilities where the rockets were designed, built, and launched. But what they really wanted were the scientists and engineers who had built the V-2, even though many if not all of them were Nazi war criminals. The USA got some and the Soviets got some, and thus the space race began. Those German scientists created the space programs in both countries, because they were in fact irreplaceable since the scientists of the Allied powers were nowhere near them in rocket science.

Also keep in mind that of all of the people living in the Western Hemisphere when European exploration and colonization began there, not one of them had figured out how a wheel worked. They dragged stuff.