That does not contest the point of earth not having infinite resources. Put another way, "one man's trash is another's treasure" meaning anything can be viewed as a resource if it can provide some kind of value.
It does not mean that there is an infinity of a specific resource.
Not too long with current stunted nuclear reactor technology. Just about a millenium for energy use on par with current EU average.
1000 years is not that long. Better we get fusion running positive or find something even better than that, which is not impossible in a thousand years.
(But perhaps people would have some laugh on how we handled specifics, say on economy, resources. Similarly like we have fun at medical medicine or astrology. They will definitely use or finally be things we have not envisioned or guessed.)
Mind you, many things would be quite familiar to a person from 10th century in today's world, barring culture - or translatable and potentially possible to educate them about. Maybe future will have it even easier, instead of telling, experiencing.
Our society is different than the one thousand years ago, but not too different.
It does not mean that there is an infinity of a specific resource.