There's no substantiation of that either way.
I have a SolarCity install that came with the house.
The Power Purchase Agreement lease seemed shady at first, but ultimately I believe it's working out better for my family than for Tesla.
I'm paying just under 11 cents per kWh and it can only go up a maximum of 3% per year for the next ~15 years.
The result is that solar generally has a generation cost of ~$0.04/kWh (which includes the cost of the land) but meanwhile you have customers happy to be paying $0.11/kWh. The trade off is the one-time cost of installing it on individual roofs is more labor intensive than doing a large-scale installation in a field somewhere, but that just means it's competitive rather than having a massive advantage.
You can absolutely draw adverse inferences from Tesla's refusal to report certain straightforward, useful numbers. For example, their refusal to publish any real safety statistics, to the point where Elon Musk himself has to invoke rubbish numbers like the 'community tracker'.
If, after all the lawsuits and accusations of failure, and the reporting about the near-zero deliveries and idled factories, the Tesla Energy division is giving you no numbers on the solar roof, and is lumping them together with a totally different product like batteries, there is one thing and only one thing that that means: the numbers are awful.
I don't think that's the true at all. There's a vast and visible footprint we can see with batteries (pretty sure every major solar company in the U.S. that has a battery storage option does at least some Tesla) that has no equivalent with solar rooftops. The former are ubiquitous while the latter are so far as I can tell almost entirely non existent.
And if that's too light on data I'll put it this way, I'm reasonably confident I can find 10 solar companies that install Tesla batteries for every one that does Solar City roofs.
Even if its low for solar, it doesn't mean it was a bad deal. He acquired existing customers he could sell other products to.