Depends how much money is available for driver development.
Which rally drivers had/ had a back ground in motocross, skiing etc before driving rally cars?

Both the asphalt karts and the dirt karts are good for young drivers before they can drive on the road and at full size race tracks.

Production road car racing on race tracks can be useful. Does Scandanavia have tar seal race tracks rally events where road cones and tyres are used to make extra curves in tar seal race tracks?
Tar seal hill climbs?
Canadian, Australian, NZ targa events - a week of driving on tar seal stages in one go.