Of course you could do the same with companies like Celsius and insure and regulate them better, but in the end customers are paying for it, it doesn't come free. Also big banks do still fail, are you aware how much money has been paid for bank bailouts just in the past decades? The thing is many don't notice they're paying for it, because they don't understand where the money comes from.
My argument is that Celsius would never have gotten as big if the customers knew what happens with their money. This business model shouldn't even be legal, same as what many more traditional banks are involved in. In fact, often it isn't legal in the first place even according to current regulation. But once they get to a certain size, laws don't apply to them as they apply to the rest of us. This is a problem, regulation is clearly not working properly in the banking sector.
Account holders shouldn't have lost (haven't checked) but the stock evaporated overnight, so anyone holding any shares lost everything in a blink.