Stream2 was called "operating system", but due to the fact, that it was still based on the CPCs' own operating system, it was rather an extension like GEOS or MS Windows 3.11. The advantage of this concept was, that it is still possible to run smaller [[Locomotive BASIC]] programs and a some of the old CPC software.
A big problem for the success of Stream2 was, that it was commercial software and copy-protected. It's price was relative high. Released in the middle of the 90ies, when most people weren't interested in spending money for CPC software anymore, it hasn't been sold very often.