I drove my Stock Jeep TJ 40,000 miles from Alaska to Argentina. There are Jeep dealerships in every single country along the way, so getting parts was not an issue in the Americas.yes you do see a few patrols and a few mitsi , even the Odd Rolls Royce capetown to london ! but you will see far more of the others and even Unimogs than you will american iron , which is a bit of a pity as there are some real interesting base units .
Zero breakdowns meant that was no issue for me.
Africa and Central Asia are a different story.