alt Hacker NewsThe example you chose is of a mirror based Solar system, which yes, is an obsolete technology.
Direct solar continues to be installed at greater amounts every year and coal is economically uncompetitive with basic anything (which is why it is collapsing), and especially against natural gas.
You're exactly right and it raises a question for me. Why do energy generation topics bring people out of the woodworks who cite some very idiosycratic one-off and use it to make out-of-proportion declarations about the utility of a given technology? This is the second one I've seen suggesting solar is doomed when they mean mirrors.
On twitter I saw someone claim PV is useless for heat because non-PV solar water heating is just so much more efficient. Not even true (I think it's a approximately a wash, different advantages in different applications), but very strangely in the weeds on a specific topic. Much too narrow a factual context to substantiate general level claims about solar as an energy writ large.
I think for whatever reason the missing the forest for the trees trap is really potent in energy discussions.