Different kinds of architecture fit for different kinds of companies. Real microservices architecture with very high granularity fits for companies that need to make hundreds of developers work on the same software. Microservices allow splitting responsibility zones between huge amount of small teams but bring additional operational overheads. Monolith might be comfortable for small custom projects where the only team do changes in the product. The space between these two edges includes many variations with different modules granularity.
Virto Commerce has a flexible modular architecture that allows developers to select the required granularity. Each module might work with its own database and be responsible for a very small functional chunk, so it would be possible to extend the platform in a microservice way. The out-of-the-box platform contains subsystems and functional modules that are more close to Service-Oriented architecture and may use both the same database or dedicated databases. Some partners who deliver a platform to mid-sized companies prefer to work with it in a monolithic approach just because it is more comfortable for them.
Conclusion: the out-of-the-box platform is more close to a service-oriented architecture, while companies can select the approach that fits them best when extending the system.