Economics is the allocation of scarce resources. The profit seeking theory that seems to lead our planet towards the detrimental current situation is pessimistic, yet hopeful. Our values define profit, and economics is a tool to achieve it. Therefore the problem isn't with economics per se, but how we motivate ourselves to interpret its potential and application. Economic growth can be 100% sustainable, or why not even additive. Why not hypothesis a system of goods and services for comfortable living that can add energy, clean and fertilize the socio-ecosystem.
Our tax system contributes to our misdirected economic growth. Finite natural resources have the lowest tax level compared to labor, which is essentially time. Our sun is an endless source of energy as is gravity and tides, however we focus on spending som many units of energy to extract fossil fuels that the ration of return is increasingly unfavorable. Our human condition makes deep assumptions that formulate problematic questions. Like the failure of the GDP (Gross Domestic Prodocut), or PPP (Purchasing Power Parity) models to differentiate between destructive growth, building more schools versus prisons and no regard for intrinsic or cultural values. There will always be imperfect information, however the linear thinking of contemporary economic production doesn't seem to have the capacity to entertain a long term dialogue. Do you think there was a million years discussion at any of the last economic summits? And why not, is economic growth hindered by deeper political power structures? Why do we assume capitalism is natural? And why do our societies need a crisis to make a change?
Milliongenerations can help economics by postulating new measurement methods and putting forth an ethical code that will generations to use economics for our posterity.
Not sure growth is sustainable. With respect to any physical quantity it is not. A 2% annual growth of something over a mere ten thousand years would result in more of that than there are elementary particles in the visible universe, so it is way beyond this planet and still way below its potential in time. With knowledge this might be more subtle, but if it requires a physical basis in reality it can not grow at significant rate for long periods of time.