The prices have to reflect the costs. If the Paraguayan operator can sell data in Europe and USA so cheap and still make some profit, that means that the regulation was not the factor that pushed down the prices, because market pushed it even lower.
Discussion
Prices are capped on the downside by costs, but not on the upside. E.g. Veblen goods.
I don't think your argument that prices are high in Europe for the reason of regulation is supported by evidence. There are larger factors at play. To take one small example, the cost of erecting a tower in Paraguay is lower because wages are lower because living costs are lower because the GDP is lower. Because operating costs are lower you can offer lower prices. Regulation may be a factor but I don't think it's the main or only one in this case.
I am not saying that prices are high because of regulations. I am saying that market is what gives low prices regardless of regulation. The claim was that European union's regulation will tame the market and bring low prices. Yet I'm not in the regulation of prices and I have lower unregulated price also in Europe!
(Side note: The cost of erecting tower is Paraguay is probably not lower, there's much less capital in Paraguay. But that's not the point, I am talking about roaming data, not local data. )
Ah ok, then I agree. Trying to use regulation to bring low prices is a recipe for disaster.
Seen some prices of poland mobile operators. Or in Spain. Czech operators are expensive even within Europe.