Good question: let's take a couple of examples of the practicalities:

Visas:

I'm going to choose Colombia, the USA, Canada, and the UK as comparators here, for the first comparison. For Colombians getting a visa for the USA, Canada, or UK is time-consuming, difficult (perhaps not possible), and expensive; for example the cost for our UK multi-entry visa was USD 1137 (!); it has just taken us more than 3 months to renew a visa for Canada. For passport holders from USA, Canada, or UK to visit Colombia the cost of a visa is nil, because no visa is required.

Second comparison - A Colombian wishing to travel in Southern Africa must obtain the RSA visa in Caracas, the Botswana visa in Washington D.C., and the Namibian visa in São Paulo. Since the clock on the RSA visa is running the moment it’s issued, we had to take intercontinental flights to get the others as soon as possible to avoid receiving the third after the first had expired. The paperwork and cost for courier services was significant in addition. For someone from the USA, Canada, or UK to get visas to visit these three countries the cost is nil, because entry is visa-free.

Solution - visa-free travel.


Travel costs: here I'm going to compare Colombia and Denmark - for a Colombian to pay for the ferry from Denmark to Iceland (two PAX one car) would cost 11 months average post-tax income whereas it would cost a Dane one month's income.

Solution: geopolitical commitment to reducing income inequality (yes, right - easy!).

For these reasons, among others, you will not find many travellers from South America or Africa travelling in the USA, Canada, or Western Europe. You do find large numbers of South Americans travelling in South America (we've met motorcyclists from Chile in Bolivia for example) and lots of Africans travel in Africa (we've met many Africans "overlanding" in Africa). Interestingly we have met travellers from Colombia and Argentina in Australia. A visa is required, however it's online and fairly simple.