Oh, and I forgot another great issue that made a lot of companies developping their own PC/windows-based solutions : PANELS. The panel solutions provided by the main players were quite horrific : proprietary, slow, buggy, limited, very expensive, bad at commissioning (speed, firmware/software compatibility issues). Siemens Simatic HMI from the '2000 decade was especially lagging and a few generation behind those from, for example, Allen-Bradley with the PanelView +/CE range, based on... Windows CE.