Some comments on Slovenian cycling, how could it happen. If you start cycling, as a young boy or a girl in Slovenia, some cycling clubs do exist, getting older, you can join clubs like Adria Mobil. Here some bigger companies do invest the money. Some (amateur) races and nationals are organized rather well. I would say at this "junior" level things are rather OK. Cyclists like Mohorič do show that. The problem i guess becomes going pro. Here i would say you are more or less left alone to figure it out and your options for sure aren't somewhere in the range of becoming a future captain at some big pro team.
In Roglič case i would say no need to analyze that all that much. There is like 0% chance you can repeat that in foreseeable future. That is if you are going after the pro cycling crown.
In Pogačar case i would say he was brilliant as a junior, ten years back already and got noticed. He likely seen Roglič do it, and likely Hauptman & Co., following Pogačar progress closely in the last decade, being in the position Hauptman is, at UAE, and being selector for Slovenian national team, that for sure played a mayor role.
Moral of the story, for all that to happen, especially Pogačar, Slovenian cycling had to be represented in the peloton in the past. It always was, we just didn't have such big international stars, that indeed is new.
In addition we do like sport, and do occasionally surprise the world audience. For example Tina Maze, likely most versatile alpine skier ever, still holding world record, points in one season. Roglič was a ski jumper, well, there is Peter Prevc, holding a world record, points in one season. Likely you know Dončić ... What i am trying to say is i am not all that surprised Slovenian(s) can do it.
Now cycling is a national sport in Slovenia, before Roglič i would say it was more reserved for people knowledgeable in cycling. Still respect for races, such as the Tour, Giro ..., that was always huge, regardless of the fact Slovenian cyclists didn't (always) win. We have our cycling subculture, for example Primož Porenta is making comeback this year. Love him or hate him, he can push the pedals.