So do the supercomputers exist or not?
Yes, they exist. Full title is yet to be shown. But the as-of-yet-available evidence there, anyhow, seems supportive of the claim that Dr Wright is the majority owner of the company that owns the world's #17 supercomputer.
there's youtube clips of him talking about his super computer, and also of one of his staff talking in great detail.
there's also lots of his lectures online, and they're quite detailed and he seems to have been lecturing for years about computing, security etc.
he had a youtube channel but its been taken offline. i managed to download most of the videos before it disappeared, so if helpful i have them archived
heres an example of one of his lectures. theres lots of them
https://www.youtube.com/watch?v=qq_kVixpxrIheres an interview on computer security
https://www.youtube.com/watch?v=pyxyhWEF4rEan interview..
https://www.youtube.com/watch?v=fAyWT3nljBIanother example lecture
https://www.youtube.com/watch?v=jH9rbPbgjIEheres his youtube channel. as mentioned, lots of videos of his family doing very normal and fun family type stuff (granny dancing to Gangnam Style, Craig Wright, exercising at the gym etc). and two technical videos, one by him and one by one of his employees talking about their supercomputer project. it seems quite impressive. he does mention bitcoin mining in there... the video was dated 2014, and he had a pretty powerful super computer (lots of xeons with gpus programmed in cuda etc). a bit late for gpu mining, in 2014, but if he had it in 2013 or earlier then it would've been mining a lot of coins.
https://www.youtube.com/channel/UC61KC8uew8xuNAs42A-yI7w