Boring company is also not yet a failure, and has recently built several tunnels. Neuralink is an early stage research company and is still humming along. It may fail some day, but it certainly hasn't failed yet. As for Hyperloop, he specifically said he wasn't going to build it, and several companies are still working on it, including in China:
https://futurism.com/the-byte/china-maglev-vactrain-hyperloo...
None of these things are "failures". They may become failures one day. It'd be crazy if some of them didn't. But you can't count a research project as a failure just because it doesn't have a product yet.
None of those companies have any real success to show for themselves. They haven’t met the hype that Musk has put on them or shown any real progress in reaching that hype.
I can at least understand you saying it might be too early on something like Neuralink, but I don’t understand calling Solar City a success. Musk had to bail it out with his other company in a deal shady enough to trigger lawsuits.
You choose 1024 people, and you send all of them a prediction about one upcoming sports game, free of charge. 50% get one prediction, 50% get the other.
Next week, you have 512 people who think you can guess pretty good. You pick another game. 256 people get one prediction, 256 get the other. The following week, 256 people think you got two in a row correct. You send 128 of them one prediction, etc. etc. etc.
When you're down to 1 person, maybe they'll pay you for the next prediction.
A track record of success is not sufficient evidence, especially when cash has been cheap for the past two decades and especially when even the first random success (selling Zip2 to an over-eager AltaVista) paid off so well.