Again, some facts may help this.

The Open Championship was the first ever Open championship to be played. It is know as the Open Championship, because that it exactly what it is called. When other countries introduced open championships, e.g. South Africa,Australia,they prefaced their tournament with the name of the counrty to avoid confusion. That is why the only championship allowed to call itself 'The Open' is the first. When Americans call it the British Open, they are refering to a tournament that does not exist.

It has lead the way in widening the field,introducing qualifying competitions overseas in a pursuit of the best possible field. If you go back thirty years ,you will find the Open field carried a wider field from the whole world, whiler the US OPen had 99% Americans and non USA players were admitted reluctantly.