From nginx.com/blog/building-microservices-free-ebook-… it says somewhere that several services using the same database is one of the worst dependencies to start with. As you change the schema, you (might) have to change all the services. Which means there's no separation of logic/storage there. And tightly bound services aren't microservices in that respect.
The database dependency as a single point of failure can be mitigated by running the database in a failover cluster. From there, you might consider using a database cluster to host several independent databases, one for each of the microservices.
You might reap the benefit from uncoupled services and mitigate the single point of failure on the database.
Hope this helps.