The GDP would be 10 times higher. It wouldn't be a lie. If the government wasn't completely blatant about it maybe store owners would only raise their prices by 9.95x and there might be a real GDP boost as well.
Is it stupid? Yes. Is it a straw man? Not so much compared to what is done in practice. When people seriously say that the policy is to "stimulate the economy" they mean incentivising people to consume rather than save. This has a positive effect on the economic figures but it is madness to believe it is setting up a better future; because setting up for a better future generally involves saving in the present.
> And since no one is suggesting that...
I haven't seen anyone propose a plan to tackle wealth inequality that doesn't involve confiscation and redistribution of some form or another. The argument is over whether that is appropriate or not.
As for GDP it is generally accepted that setting up a free market and leaving it alone maximises the GDP. There is lively debate about whether than is the best outcome. There is a serious argument that lower-than-maximum GDP with resource redistribution to the poor is better - which is what happens in practice.
> certainly not refuting, the elephant curve
There is nothing to refute. Inequality is not a problem - people can't even detect inequality! Nobody has a gut feel for it and the average level of mathematical intuition isn't high enough to understand the charts. Certainly people can't suffer because someone else has it really easy.
People suffer when their lifestyles deteriorate and we should be focused on preventing that. That is a completely different problem and one that actually deserves attention. The living standards of poor and middle class people is a real and ongoing issue that should be focused on. It does not matter if dealing with that makes the rich ricer. And in that context, the elephant curve can reasonably be interpreted as a massive success story that we can all be proud of as millions are lifted up to a better standard of living.