Politics plays dirty pool when elections are on. The mention of money over ten years is total nonsense. There are no fairies at the bottom the garden. Its like a blind folded man playing darts!
Playing outside the rules
The short answer is that for the four years following a budget – the so-called “forward-estimates period” – there are rules about banking spending cuts.
During those four years, cuts need to be specified, or economic parameters need to be varied. And with good reason. That way the actual assumptions the government is making, however fanciful they may be, are plain for all to see.
Once beyond the four-year period no such discipline applies. This allows the gov't to make no specific claims about, for example, tax cuts they plan to deliver without having to be at all specific about how they are going to pay for them.
This is all just a conjuring trick. Politicians try to get us to focus on the tangible, specific thing we want – tax cuts, more money for hospital or schools, – while obfuscating how they are going to pay for it.
It’s dirty pool. It’s not cricket. It’s the kind of thing a mob accountant does.