For many role-playing games, worldbuilding is much less important than storytelling. This leads to very linear adventures where the GM is just regurgitating the printed text, and the players are being herded along like mindless sheep. The primary reason for this is because it takes less time to get products to market, which equals higher profits. This subtle change diminishes the gaming experience for both players and gamemasters in more ways than you might imagine.
Many RPG games and adventures today don’t even try to create an immersive environment for the players. They often treat the gameworld more like a prop than the character’s homes. One example, which will remain nameless, stated in their adventure [paraphrased], “The PC may acquire the information with simple skill checks. However, feel free to roleplay the interaction if you want to, but you will have to flesh out the NPCs.” This is just laziness and breeds lazy GMs and players who just want to zip through the adventure as fast as possible so they can get the most experience they can in the shortest time.
Everything and everyone must be equal. All character classes must be balanced. PC races must be fair. And now, your character cannot acquire too much or too little treasure than their level allows. Otherwise, the character will be too powerful or too weak for the story to continue. This is the most frustrating part of this whole, “Story-First” mentality. If a game system is so fragile that it breaks if a character acquires a few less or more magic items, then the system is generally broken. In a living breathing world, if a 1st level character gets her hands on a +5 vorpal dancing greatsword, she better practice the “keep it secret, keep it safe” principle. Otherwise, there’s an NPC Lord out there who will take it away from her. In a story-first adventure, there are no NPCs outside those mentioned, and the story doesn’t say anything about them robbing a PC who cannot protect her wealth.
The gamemaster of a story-first world has a set path the characters must follow. Sure, there may be some branches here and there, but the direction through the story is always set. If the characters decide to go off script, the gamemaster flounders and doesn’t know what to do because there is little to no information to draw upon. However, if the game world followed a world-first philosophy, the GM would have plenty of information about the environment to continue extemporaneously, regardless of the character’s decisions. In this way, the story-first way is a bane, and the world-first way is a boon.
When players realize that  they have little say in the direction the story is headed, and  they are limited by the story on how successful they can be, they are not as invested in the game. They may pull out their cell phone, their laptop, or even start nodding off (I saw these things happen at DragonCon). Disinterested players equal fewer sales for game publishers, which means that they have to push for even faster time to market – a vicious circle.
Conversely, if the players have lots of leeway in their decisions and are rewarded/punished based on those choices, they are much more invested in the game. Take the best selling D&D module of all time, I6-Ravenloft, written by Tracy and Laura Hickman. Over half of the modules 37 pages are devoted to worldbuilding and most of it in in the front of the book before you get to the adventure. Even today, 36 years later, a PDF version of the book sells for just $1.00 less than the print book sold for in 1983. If game publishers take the time to use a world-first process when developing their adventures, players and GMs will be happier, sales will increase, and they will make higher profits in the long run.