In Sydney, a city of 4.5 million, give or take, there is one shop, with two outlets, selling plastic kits. Nearby, well a few hours drive away, there is one large retailer of kits in Newcastle, a city of about .6 of a million, that seems mainly to survive by on line sales. Melbourne, with a population of 4.3 million, has just two retailers of plastic kits. (Mind you, the same comparisons can be made for train sets and the like).
There are a few other retailers in outlying areas, but no where near what things were like even in the 1990s.