How would you know this? I mean you (nor I) have any idea that they will rush their players? Serioulsy have tey said "Ready or not the kids will play"? I mean it's not IDWT running Vegas.
How do you know their scouting network and development curves are that bad? I mean did you know from day 1 where Columbus, Minny and Nashville would be? I mean Nashville has built consistently over time. Minny has been close but they have had their ups and downs and until recently Columbus has been a horrible franchise (part of it was IDWT, part of it was not spending money early on, a lot was missed draft picks).
I personally think Vegas put toghether a pretty good infrastructure as far as management, I'm not that well versed on scouting and who they have but if you know their scouting department will fail please explain why.
I don't know their scouting department specifically, but I do know it takes years to develop a well-structured scouting network and development system for new franchises, even if they have a veteran GM.
But let's say they draft average or above average for an NHL team. Free agency and trading is much less of a viable means of creating a competitive team than it was 10 years ago. This creates a problem:
Players taken in the 2017 draft at 6th, 13th, and 15th won't likely be ready for the NHL for 2 or 3 years. They're probably 3 to 5 years away from becoming actual impact players at that level. Players taken in 2018 (unless perhaps the 1st or 2nd overall) won't likely be ready for 4 or 5 years from now and are even further away from becoming impact players.
So Vegas has a choice. They can either rush players and have a better roster now or they can try to let players develop slowly in which case they're looking at having a roster with the same quality (quite low based on the ED) for 3 to 5 years.
Rushing players is a band aid and creates problems further down the line.
Obviously, then, the team should be patient. The problem with that approach is if the team continually finishes near the bottom for 3 to 5 years, that's toxic to the team's environment. Once young players ARE deemed ready for the NHL, they're entering a locker room which has little established talent and a losing culture. We've seen teams go this route before -- the Jackets, the Oilers, the Islanders, Arizona, etc.
Unless Vegas gets a Connor McDavid or a coach like Babcock and young player like Matthews, it will be extremely hard to buck this trend in 5 or so years.