That's interesting actually. Vic & Thomas have known each other since they were 10, but they haven't been "a band" that long, you're right. Their fashion and musical style has definitely changed since they started and they're still experimenting with different things, which I think is great. They are definitely extremely talented though, I forget they're in their early 20s when I hear some of the lyrics & guitar skills, so they definitely deserve their success.
I watched something or read something somewhere where they said there isn't really a pub culture or anywhere for bands to play gigs in Italy like there is in the UK, hence why they started out on the streets as buskers. They took a high risk high reward strategy by going in for X Factor and it definitely paid off, plus Eurovision. I think it's partly all that & partly their confidence and not giving a tit if you like them or not that's made them a big success.
Added to that - about their evolution - their first EP "Chosen" is a pile of shite quite frankly. Il Ballo Della Vita is much better, but I still skip a few tracks. Teatro D'Ira vol 1 is one of only 2 albums that I never skip tracks on (the other being Jagged Little Pill by Alanis Morrissette) - every single track is amazing. Can't wait for the new one!!