This is a common misconception. The ideal launch point for any orbital inclination is the latitude that corresponds to that inclination. KSC is ideal for launching into a 28.5˚ inclination orbit. The “throw” at the equator begins to be offset by the need to spend propellant to go northward. Eventually, a 90˚ polar orbit would have to counter the speed of the equatorial “throw” that had seemed to be an advantage.

If I were only allowed one launch site on Earth, then I would choose the equator, because the difference is not terribly great, only a delta-v of around 300 miles per hour more from the equator to a 60˚ orbit than launching from 60˚ latitude (less than 2% difference), but there is definitely an advantage to launching from the right latitude. However, it is better to distribute them similar to how we have them now: Equator (e.g. Kourou, French Guiana, KSC, and Russia’s northern (almost 60˚) sites. Farther from the equator gives nice entry points to sun synchronous orbits, which are slightly retrograde (greater than 90˚), which is why these orbits are the focus of discussion for the New Zealand site, the Scottish sites, and the Alaskan site. The Equator is nice, as many payloads in the past have been destined for geostationary orbit, directly above the equator, giving an advantage to Arianespace and its Ariane rocket family.

Virgin Orbit’s advantage is that it can fly to any (or almost any) latitude so that its airplane-launched rocket can launch from the most advantageous place. This is an advantage not available to fixed-location spaceports.

On the other hand, launching from a higher latitude to a geostationary orbit can be very costly in delta-v, as an orbital plane change is needed. That delta-v can be a couple of thousand miles per hour, whereas an equatorial launch requires no plane change and no delta-v propellant expenditure.

To paraphrase Sir Walter Scott(?): Oh! What a tangled web we weave, when first we practice orbital mechanics.

Original Mark is correct, there is nothing to stop South American countries from having strong economies. A century ago, Argentina was in competition with America for economic dominance in the Western Hemisphere. Then Argentina elected a dictator, and that competition was over.

Oh, wait! I’m wrong. There is something that can stop Western Hemisphere countries from having strong economies.