I came up with it myself. It's possible there's prior art but nothing that I've read personally.

I don't think it's a particularly revolutionary idea because sovereign wealth funds already exist. Improving productivity means using less labor which means lower income tax revenues as time goes on (and that's what you want - higher productivity, fewer labor inputs).

And yet, the government needs revenue. What's growing? Wealth. Liquidating wealth to pay taxes is problematic. Hence the sovereign wealth fund. You can apply this to most forms of wealth - even publicly traded stock, real estate, crypto, and artwork.

I've proposed it on this site several times in the past.