Yes it is more expensive but as you probably already know land appreciates and house deprecates.
So if you have 2x 250k regional properties being 50k land with a 200k house on it in theory you have 100k land and 400k house.
Where as if you have a 500k capital property with a 300k house and 200k land you in theory have double the land value of the smaller cheaper houses and it should increase by more over the years.
As there is more demand for the capital property and migration increasing and jobs education and amenities better in the capital than regional this is further way they will increase in value more than a regional which don't have the same demand and might only have 1 or 2 main industries.
I don't know about that, I understand Melbourne has a growth rate of 1.8%, some regional areas have a growth rate 0f 6% and plenty of migrants and 0.5 %vacancy, a much higher demand than some capitals that have a vacancy of about 4%. In any area there will be location that are desirable and locations that aren't a few hundred metres can be the difference.