You can get USD for BTC right now, you've been able to get if for nearly a decade and there have never been as many reputable exchanges as there are now.
You said they "tend go down for maintenance" on "any big price swings" but were only able to muster one example of one exchange going down "for maintenance" on one price swing (Bitfinex).
The others, as the articles point out, were trade volume related (which is also a problem, but much less sinister).
There's no evidence this is some kind of grand conspiracy like you implied. There's plenty to criticise in Crypto, but little evidence for what you actually claimed.
No, I'm not challenging the premise, I'm challenging your framing.
Your comment implied sinister intent: That exchanges go offline at key times in order to scam people.
No evidence was provided of that. The sources you provided point to technical problems that are perfectly understandable during a massive, unpredicted surge in such a technically complex field.