I reckon that in five years from now everyone can give up building custom model tractors. It will just be narrowed down to fitting slightly wider or skinnier tyres and fixing factory errors. Most gaps have been filled and with the hundreds of models coming out every year the rest will be done soon as well.
What remains is some farm machinery, especially local build and from small manufacturers that the big boys are unwilling to take. Although even that is changing.
Is this just a grim