Thanks for the post! I just did the whole Microservices analysis thing too, and here's what I took away from it.
We have a bunch of shared databases which are used in different ways across different products, and it's a challenge to balance all the requirements on the database. There's a lot of building secondary aggregate tables, new indexes, new procedures, etc to accomodate the needs of all the users. At the risk of sounding like every NoSQL Getting Started page ever, Relational databases are great for stable schemas, but falter when they have to change frequently or dramatically. So as an integrated source of data across multiple products or microservices, it falls on its face.
However the solution to that is walling off the databases from that reach-in-and-take-what-you-want model, and instead publish feeds of data different applications can subscribe to (such as through Service Broker, or really any messaging platform). In that case, there is no problem using SQL as the source of the feed or the destination. It's not perfect, but nothing is. And it also strongly decouple the data storage and representation from the data retrieval, a critical feature of Microservices.
As far as "RDBMS is dead", that is, indeed, a ridiculous claim. The flip side of the criticism of Relational databases is that schemas exist for a reason. There is no single best representation of data, and in fact the best representation for a given application will almost certainly make it worthless to another application. So where schema is legitimately getting in the way, yeah; SQL doesn't make sense. However the places where that is the case are much fewer and farther between than many would like you to believe.
RDBMS is dead, long live the RDBMS.
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