However, this is not the case with many Sanbox MMOs. In most sandbox mmos, a service sector is established, normally in the form of a service such as, bounty hunting, transporting goods (delivery), protection services (mercenary), or even store ownership such as renting out a vendor space in your store.
A question one may ask is why is there a service economy in sandbox and not in themeparks? My guess is because in a sandbox MMO the economy is truly player driven, meaning that most goods and services are provided by the player. Another possible reason is because the game play imposes risk, rewards, and responsibilities.
In a sandbox mmo you may have to rely on others in terms of security and sometimes even in progress. This is where such services such as transportation, mercenaries, and bounties come into play. In a themepark mmo there are no such associated risks. You can never lose your gear or items, even after death. There is no need to hire services for protection in fact there is no need to even hire players for attending raids. Perhaps if there was a risk when failing in pvp or pve I can see players or guilds hiring quality players for their team, but doing this will certainly cause additional problems in a themepark setting.
But in short themepark mmos are missing the service sector of the economy mainly because players have no need or benefit to group with other players that do not share a similar interest. No, grouping for raids or battlegrounds does not count because those activities are a must for players to progress; therefore everyone has an interest of grouping to complete those activities. Unlike in a sandbox, I may need tons of goods that need to be hauled to another location but don’t have the means to do so, however; there may be other players who are willing to provide the service for the right price.