Solar panels mean a dependence on ChinaIf you're referring to rare-earth production, my understanding is that this is more a matter of where mining operations are considered viable and acceptable (largely on a basis of environmental impacts). The elements themselves are relatively abundant in the Earth's crust, they're simply not concentrated as other minerals have traditionally been (though we've done a rather good job of ensuring that concentrated ores no longer exist).
Materials dependence is also different from fuels dependence. In the latter case, short-term interruptions can have massive disruption effects on whole economies. Look at what possible military action in Syria is doing to current oil prices, let alone the disruptions of the 1974 and 1979 oil embargoes. Were material flows interrupted, what would be disrupted would be additional energy systems development, but existing systems would continue to function fine (modulo maintenance and retirement).
the endlessness of renewables may be technically true, but often not at all in practice.
There's a fair bit of truth to that. Many renewables technologies are dependent on specific and limited materials, or on complex technology stacks: PVs also require an extensive chip-fabrication infrastructure. Once it's established and producing it's pretty efficient, but having to build it from scratch would be a challenge.
You're touching on issues that many who are looking at future paths (generally: "collapse", "transition", or some combination / variant of these and other options) with cold, clear vision see.
My point is that whatever challenges renewables offer, they're out only hope, so if it turns out that they do have profound limitations, we'd best start getting used to that idea. If this means going back to animal power and firewood -- well, we have a rough idea of what sort of population can be supported on that technological stack. And I don't paint renewables as necessarily being sufficient for present-day (or even technologically advanced) lifestyles, though I suspect they might be able to offer that.