If you talk about no vendor lock in, and you'd want to take your database then to a competitor, like Google Cloud, Azure, or on-premises, wouldn't you exactly expect to do a SQL dump and reloading everything? To me, the one-click move from RDS to Aurora you describe is a nice shortcut, but it doesn't invalidate that you can still do the former if you wanted to move to the competitor. Vendor lock in seems more that you've architected your application against a system that only exists on AWS, like SQS or S3 (although, I guess, competitors offer compatible APIs for some of those, I'm not entirely read up on the state of things there).
Seems a bit of a dark pattern to have shortcut to onboard and not offer the same shortcut to offboard.
Just like easy subscribe-online publications that will have you call during 2 hours with a rep pushing you discounts or whatever to cancel such subscription.
I'd characterize this asymmetry (convenient shortcut IN, standard export OUT) as a predictable, transparent, minor annoyance -- not a "dark pattern" representing deceptive or unethical practices.
