I mean, they were already able to accomplish the one thing that most other Eurovision winners have failed to do, and that's to have a second hit after their winning song. Even ABBA weren't able to do that for a while (a few poorly-charting singles released in between "Waterloo" and "Mamma Mia").

They have a lot going for them: their music is critically acclaimed, they're young, attractive, and have very interesting personalities that make them relatable especially to fans of equal or younger ages, and they have an extremely pathos-inducing hero-ish backstory (from street performers to world-dominating superstars).

I feel like it's a positive sign that they're still gaining traction more than a month after the Contest, but it remains to be seen if they can really sustain their momentum to solidify their success; they're only one month into their reigning year, after all. I think it'll all boil down to consistent marketing and the release of more music.