The standard monthly contract price, 150kr/month or whatever, is the big number that customers look at when signing a contract. It's where the companies compete, so they can't increase the prices beyond a reasonable amount.
There's no longer the hidden cost of being caught with a bill for 500kr after returning from a European holiday.
That's true, and I agree that the high bill is nice to avoid. But also, I think it's classic pro-regulation-people to be surprised by companies levying the fee on the end customers. I guess also, that for most consumers, they would rather have some other system (reasonable way to buy cheap roaming-data?) for those European holidays instead of paying 10-30 SEK extra per month, for ever. I would guess most people don't roam even once per year.
There wasn't a good, reasonable way to buy cheap roaming-data, at least not with my German contract. 150MB of roaming in the EU was 5€ with the purchase process (via SMS) being bugged and failing 50% of the time, sometimes charging my credit card instantly while delivering the "You can use your roaming data now" message days later when I was back home, customer support could not help because they "do not suggest that the data is available instantly". n=1, obviously.
I'm sure there are lots of people who roam a lot; people travel on business all the time, truck drivers cross borders all the time, anyone living along the border to Norway or Finland goes across a lot, anybody in Skåne is an hour or two away from Denmark, and let's not forget the thousands who take the ferries over to Finland and Åland.
And who is going to buy a roaming package when you're gone for at most 24 hours? A week in Greece or Mallorca and it makes sense with something like that.
There's no longer the hidden cost of being caught with a bill for 500kr after returning from a European holiday.