Competing on the world tour is not a whole other level, it is a whole other sport.
You must change your training programme to be able to compete in different timezones and environments. Physiologically you become a different athlete. Your body clock is on world time, it has to be so you can beat jet lag.
You also have to get used to adapting, understanding and respecting the different cultures in the locations you compete in.
This is quite unlike domestic or regional competition where the differences are slight. The difference is across continents.
Then there is the attention you get from the international media and the fans. This is not your home town crowd support. This is the international audience that anticipates your arrival and feels entitled to a piece of you because they buy the magazines and the product lines you endorse. Rightly they do, because their purchases pay for your salary. This is money, this is the reason there is a world tour, you are part of the consumer product marketing and distribution chain. You are not the consumer, you are a marketer.
And of course being on the world tour means that you have to be a professional, at the national level where almost everyone is an amateur you can probably get away with not being 100% because the other guys are not preparing and performing at that level you need to be to have a sniff at the world tour.
You will need 100% control of your performance if you want to compete on tour and execute race strategy. Race strategy is the other thing that sets the tour apart from the amateur competition, everything is planned and has to be executed to the micron. There is science behind race strategy, managing your physiological resources to optimise the result based on what performance your body is capable of producing. Before the race starts, you already know when you are going to finish, it becomes a chess game to see what the other teams have planned.