> Let's imagine you use 3 different marketing providers, plus an in-house one, because you're a big company and your teams all want to use whichever tool works best for them.
> A user unsubscribes. This creates an entry in one specific system. In order for that to be reflected across all systems, it needs to be copied somewhere central, then synced back out.
The idea that it takes any longer to unsubscribe just demonstrates the marketing companies being user-hostile. Let me demonstrate why what you're saying sounds ridiculous:
A user is subscribed to a marketing provider (probably against their knowledge or desire). Minutes later all three marketing providers have the user's information.
If the system is slow, the marketing company would solve that pretty quick. If it often breaks, the marketing company would solve that pretty quick. If you run bulk loads/unloads every few days... maybe I could see that. Maybe. But the marketing company is likely going to want to fix that too.
How many users do this database have? Thousands? Millions? Databases from twenty years ago handled that just fine and quite fast too. Are you trying to tell me that modern databases are slower? Or are there perhaps too many users in the database from, eg, a dragnet?
Is the Enterprise Infrastructure Platform as a Service product truly to blame? Are you trying to tell me that the service is incapable of handling the ingress of a data point (user subscribed, user unsubscribed) in a timely manner? If that's truly the case then I have to truly wonder what else that service doesn't handle well: user privacy and information security are two top points that I'd wonder about. Competence and susceptibility to spearphishing would be some others.
Oh, right. Marketing companies aren't "user-hostile". Users aren't their target audience; users aren't their "users". Businesses are.