If your app can be DB agnostic, then what DB you use doesn't matter, so you will never need to switch it.
Also you don't need an "architect" and a "DBA" to know how to use databases properly.
Also you don't need an "architect" and a "DBA" to know how to use databases properly.
#1 - The administration of a database system #2 - Being able to write code that uses said system effectively
If you don't have skillset #2, you are going to design and build bad systems and eventually a DBA will need to bail you out. The trend is that companies are reducing the number of DBAs on the payroll because of things like AWS Aurora, so you had better get skillset #2.
And why wouldn't you want it? It's like knife skills for a chef. You should know your tools inside out.