I renewed five contracts this year, neither of them had the same amount of data for roaming as they did for local. Calls and SMS, they did (unlimited, basically). This seems to be the norm for Orange here. I would assume the same goes for Vodafone since they generally seemed to always offer less for more.

That being said, it's absolutely lovely to be able to travel for business or holiday and to be able to find your way around, purchase things and get access to public transportation information abroad. Roaming costs before that always tended to be so eye-watering that I never really knew anyone who thought they were worth putting up with. I really dislike going outside of the European Union because of them, myself, too.

If memory serves, the amount of roaming data you get is computed on the basis of 'what would you get if you paid roughly the same amount of money to a typical provider in the country where I am travelling', with some caps in both directions.

I live in Italy which has low prices, so I get 50 GB/mo for 8€ (and 200 GB/mo during the summer). Last summer I travelled to Austria and Czechia, I had 4GB available in both countries, and indeed checking their biggest ISPs' landing pages it looks like 8€ wouldn't have bought me even a gig! So 4GB is probably a mandatory minimum.

That's interesting, thanks you for the explanation, makes sense to me!