The trouble with their exchange business is they're only making 5-6.5% on half the turnover as opposed to having a 15% markup on 100% turnover if they just have a Fixed Price Tote. We all know that must be a successful business model as overseas bookies are trying to buy a share of the market.
A parallel might be CocaCola Amatil. They make 100's of millions in profit a year and own SPC Ardmona who allegedly lose millions each year. If they closed down, that'd upset a few people(aka Layers), but as a listed company with shareholders their charter is to make a profit at all costs.

I guess it's about economy of scale, Australia has a fairly small population of Exchange users compared with the UK, dunno? I hope not.