Well that's an other thing, when you look at these solutions from afar you often see the core functionality and think it's not a big deal but the devil is always in the details, the millions of small functionalities hidden everywhere for specific tasks is what makes it very hard to compete. Every company has specificities, they want to interface with $external_software, they want to import $arcane_data_format etc... You start by writing a slim and tidy database engine and the next thing you know you have to implement an MS Excel to protobuf converter.
It's easy to underestimate the complexity of an ERP for even a moderately sized company, let alone one the size of LIDL.
