Perhaps if you mean their current U12 generation will be the next golden age, maybe but that's in a long while. But that's not the problem. The problem isn't lack of youth surfaces. The problem is professional hockey infrastructure. Belarus has one professional hockey team, Dinamo Minsk, and Kazakhstan has one professional hockey team, Barys Astana. Yes, Belarus and Kazakhstan have local leagues, but these local leagues are not competitive enough, lucrative enough to help develop a young prospect into a young professional. I don't think Belarus NT even plays local league players for WM or Olympic events.
Every year the Junior teams of Belarus go to the junior championships and they do very well. Then you never hear of them again. Dinamo Minsk can only sign so many young Belorussians every year, maybe one if any. A young prospect needs to play in a competitive environment to improve, he needs the monetary incentive to play hockey over anything else he could do in life, and these Kazakh or Belorussian players just don't have that right now. My research was on Belarus not Kazakhstan so I'll give Belorussian examples to illustrate. The 2010 U20 WM class, seemed promising at the time but who came out of it. An underaged Kirill Gotovets played 2 games there, he's now mostly settled in the AHL after bouncing between the AHL and ECHL, future still uncertain. Sergei Drozd is like a 4th liner for them. No one else made it. They looked so promising statistically at the time. Go back a year and it was Drozd and Belarus 4th liner Artyom Demkov, Dmitri Korobov, no one else made it. Go back another year add Andrei Stas, Nikita Komarov. If you look at the U18 classes it's even worse. The 3 years Arturs Gavrus played in the U18 WM produced one other regular National Teamer, Yevgeni Lisovets. It's not that they weren't being successful. Those U18 years they were getting promoted, and then playing top division, winning the D1A handily every year. They were always perennial contenders at the U20 level too, it wasn't for lack of strong youth teams, so what happened? Go back to Latvia U20 in the same 2010 year. Bukarts, Kenins, Indrasis, Freibergs, Skvorcovs, Kalnins, it's not natural for entire classes of players who played well to just fade into the blue. They either need to diversify their export base like Latvia, or they need to develop their local league like Switzerland. Otherwise, they can have all the Junior success a man can ever bite off, and at the end of the day the golden age will never come.