Interesting. Perhaps it's more affordable in Australia (that's a first!), because the people I know of aren't rich, just a little obsessive ;)
I've been to factory equipment auctions and browsed online and you can get some really cheap used 3 phase machinery; as soon as something 1 phase shows up the price rockets. Businesses seem uninterested in the old equipment, but guys tinkering in their sheds love them.
AFAIK 20 A at 240 V is the most you can get from single phase in Aus, with 10 A at 240 V being a standard power point, so 3 phase is not so uncommon (even small food shops have it). Remember that it's not just a matter of high power, but dumb motors run nicer off 3 phase.