Australia raised the income tax threshold to AU$18,000 IN 2012 - https://www.ato.gov.au/Rates/Individual-income-tax-for-prior... It solves a completely different problem to a basic income. If I break both legs and can't work as a laborer any more, it does nothing for me. If I have a baby and daycare costs more than my available jobs, it does nothing for me. If I'm 56 and get laid off, or 19 and want to get a degree, it does nothing for me.
FWIW, in Finland the income tax threshold is € 12700 (i.e. you don't pay income tax for earned income lower than that) which is almost exactly the same as in Australia.
The taxation is quite progressive, so low earners pay less tax than in most European countries, and high earners pay more than almost anywhere else in OECD (depending a little on family status etc).
The main problem for Finland's tax collection is too few high earners to get enough tax revenue (not entirely unsurprisingly, because the other policy goal is a flat income distribution.)
I don't think the basic income experiment changes anything, though. It's impossible to move to BI because some people would lose money so any change would be extremely unpopular. And a change where "everybody wins" would be prohibitively expensive.
