They serve anyone with the money to pay for it. Despite the vague description of a citizens wealth status, if you actually mouse over their pay rates, different jobs have different pay even within a status tier. Then depending on what you have them paying for rent, food, religion or entertainment determine if they have money left over at the of end of any particular month. Even having children effects a persons on-hand money, adults with children have less spending money unless you issue child allowances so a well-off without kids has more money to spend than a well-off with kids

The entire system of displaying the vague status of a persons wealth is pointlessly confusing when there's a granular system under it that you have to dig deeper to see (and unfortunately still have no direct control over since each job / building has it's own predetermined numbers for pay and costs for using at any givin status setting) But well off in one job pays more or less than well off in another job. It's a pointlessly simplified way of displaying to you a more complex layer underneath

(even more annoying is that in tropicos 1 through 4 you had direct dolllar by dollar control over exactly what everything paid and/or cost with exact precision, not vague status ranges so you could set exactly what someone made per job, knew they would spend up to 2/3 of that pay for rent, set a specific building near that job for exactly 2/3 their rent and then know exactly how much those workers had left over to pay for nearby entertainment and then could set the cost of those entertainments to get back most of the rest of their money each month ~ this new system still uses the underlying mechanics of how people pay for things but doesn't let you direct control the numbers involved, only the vague ranges by status and then the buildings have predetermined numbers for each range which are not all the same)