Your examples seem to support the point you were replying to. Theranos is a perfect example of a scam unravelling because eventually the scammer needs to produce results, and not just self-referential research papers that never quite go anywhere.
There's a sucker born every minute and a skilled con man can exploit that unfortunate truism to keep a scam for quite a while. Moller's skycar is an example of a flagrant scam that lasted for decades.
> It doesn't take long to think of entire industries that are shady, from payday lenders
I trust you aren't arguing that payday lenders don't earn money!
There's a huge difference between "I don't like what this industry is doing" and "this industry is fraudulent, can never produce the goods/services claimed, and will never turn a profit for the investors".
The immorality of Pay Day is very much known, and it is not relevant because Pay Day is scamming their customers, not their investors.