(Using US definitions where "billion" = 10⁹)
I have had good luck using seconds. 100,000 seconds is a little over a day. A million seconds is a little over 11 days. A billion seconds is a little over 30 years. A trillion seconds is a little over 30,000 years. The earliest evidence of anything resembling agriculture, a kind of gardening, is from about 23,000 years ago. (https://en.wikipedia.org/wiki/History_of_agriculture)
Then I challenge them to pick a company and government program to compare profit and delivery cost. For example, Cameco, a uranium mining company headquartered in Saskatchewan has profits in the range of $200 million per year. Saskatchewan government eliminated our rural public transit (STC) because it cost $17 million more to operate than the revenue it brought in. Easy peasy. One company could have funded the shortfall and still be very profitable. Spread that across a bunch of companies and it would be little more than a rounding error in their profit and loss statements.