I think the person who wrote that actually meant not mainstream, i.e., not someone you would have heard of. Many set ups were small by "factory" standards. Studio glass is a modern term, when you are often talking about relatively small volumes of hot glass in one- or two-man operations. Glass making has been around since before Roman times. I know for a fact that the glass industry in Scotland is over 600 years old. Fuel has always been the issue, which why so many old glass foundries were near the coal fields. Before coal it was wood and the makers often moved when the supply of trees ran out. Some of the very general glass books have good introduction to glassmaking and its history.
So no, what you have is not studio glass.