Basically money and time
For a global launch you have to have a lot of money to blow at once because you need to produce enough copies for the global demand, localise the game the game into dozens of different languages, advertise in every region which takes planning to tailor advertising to each region, distribute copies (can take weeks to build up supply and ship to some countries and have the product distributed to stores which makes leaks and broken street dates more likely).
And also ratings systems which also means you have to plan in advance enough to have dozens of different ratings organisations all have rated the game and any edge cases dealt with as many regions and countries have very different standards and edits may have to be made (Countries like Australia and Germany have tight restrictions so gore often has to be cut and swastikas etc cut for Germany etc) to the game to get the the rating the publisher wants.
Basically only the biggest publishers can afford to do global launches and only for big games that are sure fire sellers globally, can afford to do it. It's not cheap, requiring a big investment all at once, and also requires a lot of bandwidth to do localisations all at once or delay the game for months to get it ready. If publishers did global digital launches with a slower rollout of physical copies that would make it easier but even then it is still a big investment.