Whose fault is it really that all content is not available on a single service? It's nobody's fault, it was inevitable given how things work.
How could you "fix" it? You'd need legislation saying that all content must be made available for licensing at the same price for every service. But that's not enough, because why would HBO sell their content to Netflix and vice versa? No, you'd have to force them to make it available. But that's not enough either, as they could just set the price extremely high. And at this point what would be the point in having multiple streaming services at all? Perhaps we need legislation that enforces separation of content producers and distribution, like the Glass-Steagall Act but for TV, or Net Neutrality?