That's strictly true for standard definitions of ERP, but it's a rare enterprise that doesn't already have adjacent software they've licensed to specifically support parts of their business. This could be freight & logistics, or warehouse management/inventory, or QA/Test, or RMA, or whatever. Convincing someone to move away from Oracle or SAP is a nonstarter for a startup. It worked several years ago for Netsuite, which advertised itself as the first "cloud native ERP" and was widely lauded for being so much more easily customizable than Oracle (so Oracle bought them in 2016).
I don't think starting a new ERP company from scratch makes sense for anyone. The best you would likely do is to become either a minor player (just look at the array of CRMs that aren't Salesforce), tailored to a very specific market niche, or an "ERP adjacent" platform of some kind. That last bit is the obvious play. The bread & butter of Enterprise Applications IT departments around the world is to build custom stuff that inherits data from ERPs or feeds data into ERPs and similar mission critical business platforms. Speaking as a guy who ran one of these departments in an F250 for about ten years, most of what they build is pretty crappy.
I don't think starting a new ERP company from scratch makes sense for anyone. The best you would likely do is to become either a minor player (just look at the array of CRMs that aren't Salesforce), tailored to a very specific market niche, or an "ERP adjacent" platform of some kind. That last bit is the obvious play. The bread & butter of Enterprise Applications IT departments around the world is to build custom stuff that inherits data from ERPs or feeds data into ERPs and similar mission critical business platforms. Speaking as a guy who ran one of these departments in an F250 for about ten years, most of what they build is pretty crappy.