Agreed. However, IMO SoftBank is just a symptom, when world's banks are (were) so liberal with the money, you get these type of deformations, zombie companies is another one.
There simply isn't $200bn of real positive capturable return investment opportunities out there available at once. Anything physical would be hopelessly bottlenecked by its own size and would be unable to scale rapidly enough for the investors. So it had to be thrown at all these hugely speculative projects with the goal of capturing entire markets.
The real problem is that, due to a century of fossil fuel dependence, there's a huge amount of wealth concentrated in weird desert monarchies.