All of the issues with SQL, including strong consistency, data normalization, table JOINs, etc., mean that any RDBMS is going to inherently going to be limited

All of the issues with SQL, including strong consistency, data normalization, table JOINs, etc., mean that any RDBMS is going to inherently going to be limited in its viability to scale compared to a properly architected NoSQL database. Disclaimer: I work at ScyllaDB. A LOT of our migrations are from people who got started on MongoDB, and then it fell over. Another group come from DynamoDB, and then they see their monthly bill. There are also people who have moved to Scylla from PostgreSQL because it fell over, or those who blanched at their Oracle bill. Scalability is not inherent to SQL or NoSQL. It requires both technical features as well as economical offerings. It is a quality of a product made with users and real-world workloads in mind. As in all DB work, YMMV.