Per capita power consumption doubled in the past 50 years, and there's no reason to think it won't again -- most of the world's population is still in developing economies. Population growth will also continue, although not at the same pace as in the past. If your point about long-range social forecasts being hard is that this article had no business being published in a reputable journal, I agree, but if we're going to debate the merits of the article we have to make some long-range projections.
As I said earlier, you cannot reasonably compare growth rates during early adoption phases with steady-state capacity, and you are also confusing installation growth rate with production growth rate (which is the derivative of the former).
While indium, tellurium, and other uncommon and/or hard-to-refine elements -- which are critical parts of modern solar cells -- are technically not rare earth elements, they are often treated as such in popular media and policy analysis.
So, congratulations on finding a pedantically correct but practically irrelevant issue with half of one of my points, while ignoring or pretending away the rest? Maybe you should try to debunk some of your own bullshit sometime.