No utility has gone 100% solar with their customers getting a reduction in their bill. There is no other evidence needed because it's the unassailable argument. That's the argument that must be defeated, and deflecting to anything else is evidence of no argument.
Your so-called citation is not credible because you simply list names and organizations. That's not how citation works. I could counter by citing The Science, all of it. Just go study all of science, and then get back to me.
Though this is completely unnecessary given the single unassailable fact presented above that requires no further support, I present this as well.
I guess China is building all those expensive and polluting coal plants because... they're dumb? Coal is the #2 electricity source for the US (behind natural gas) because we're dumb? Coal is the largest source of electricity globally because the whole world is dumb?
I've got no particular interest in coal being the future of electricity generation and no opposition to the possibility of solar or wind sucking less in the future. I don't live in the future though, I live right now. It's absurdities like "As of 1989, Coal and Solar PV were of equal cost, $ 0.30-kWh" that undermine the credibility of the cause. No reasonable person would uncritically accept that as truth and instantly be converted to that religion. Only the most unsophisticated thinkers would fall for such a statement.