Like tidying your sock drawer instead of studying for exams, the backpacker tax distracted the final week of parliament because it seemed like a task that could be achieved.

It didn’t turn out that way, but it was supposed to be easy – one of a couple of things that would allow the Turnbull government to be seen to “Get Things Done” in the promised “Year of Delivery”.

But in the grand endeavour of getting the tax system to deliver enough revenue the new measure is still not much more significant than tidying the sock drawer. The final version of the bill, which ended up requiring the support of those supposedly fiscally irresponsible Greens, will raise a few hundred million dollars over the next four years.

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While voters watched with bemusement and dismay as the grand theatre of their democracy spent days bickering over the exact rate of tax working holidaymakers might pay on their fruit-picking earnings, and whether assorted crossbench senators were rotten scoundrels for welching on their deals about it, a couple of truly big ideas got much less attention.

They’re not finalised and still to be subjected to the full blowtorch of big-business lobbying but the two ideas inched forward by the treasurer, Scott Morrison, this week could – if they survive – make a real difference.

The first is the so-called diverted profits tax – the Google tax – similar to the tax introduced in the UK in 2015 to stop multinationals coming up with convoluted schemes to shift their profits to low-tax or no-tax jurisdictions – the kind of schemes that mean companies including Google and Facebook have paid very little tax here. So far we have an exposure draft of the legislation, with submissions due by Christmas Eve, which doesn’t leave a lot of time to bring it in before the scheduled start date in the middle of next year.

The government is counting on getting only about $100m a year from that tax, choosing to err quite dramatically on the side of caution, but depending on how it is enforced by the tax office and interpreted by the courts it could raise a great deal more than that.

The second is the government’s long-overdue concession that something is very, very wrong with the amount of revenue it collects from offshore gasfields.

As campaigners at the Tax Justice Network have been pointing out for a long time, there’s something amiss when Australia will become the world’s largest gas exporter in 2020 and is forecast in that year to get just $800m in revenue for its resource, while Qatar – the country we will be overtaking – will be getting $26bn.

The money that can be reaped from multinationals paying their fair share of taxes could be more than $400bn over the next 20 years, according to the Tax Justice Network’s calculations. But that assumes the tax can be applied retrospectively, which the treasurer appears to be indicating is unlikely, but without which the whole exercise is a bit pointless.

The government plays up the backpacker tax because it assumes – often correctly – that it will be judged on short-term wins and losses, on whether it ends the year “on a high” and whether the prime minister can be seen to be notching up some “wins”.

But voters are seeing through those kind of measurements of success and failure. They know the incremental scorecards that assume such importance in the corridors of Canberra are often based on second-order things and that the real stakes are much higher.

And they’re right. Forcing backpackers to pay some tax is welcome, as far as it goes, but not nearly as important as making sure the government follows through with its plans to properly tax multinationals.

That’s before we get to the argument about how the additional cash should be used – the crucial, central policy fight we almost had in 2016 election campaign before it drowned in a sea of slogans.

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Should any additional revenue make up for that forgone with the Turnbull government’s $48bn in company tax cuts – the ones that were going to be the “first order of business” for the new parliament before it was clear they were unlikely to pass in their entirety – or should it be used to ensure the continued provision of quality health and education, adequate payments to the unemployed, adequate care for the disabled?

Will Morrison prevail with his argument that we absolutely have to keep up with other developed countries – Donald Trump’s plan to reduce US company tax to just 15%; Theresa May’s promise to take the UK tax rate to 17% – to maintain investment and economic competitiveness?

Or will Bill Shorten be able to articulate and explain Labor’s message of inclusive growth – that spending on health and education to prevent rising inequality is a prerequisite for growth, not something that could be afforded after the benefits of tax cuts “trickled down” through the economy.

That’s the argument were were supposed to have in 2016 and it has an importance beyond even its far-reaching economic consequences.

The low-tax trickle-down economics of the US and the UK must bear at least some of the blame for the rising inequality and the voter backlash that has pushed politics in those countries to destructive, divisive extremes.

A lot is at stake if the Australian parliament gets around to the really big arguments next year. Or it could stick to the sock drawers.