Why do companies require special systems?

Sometimes the regular systems may have a lot of shortcomings, and they do not perform the required work as planned, so companies need to request special systems that perform the work as required, and there are also companies that may have a new vision that they cannot achieve with the available systems, so they resort to requesting their own systems from companies Programming and on-demand systems often have completely new ideas and new ambitions that companies aspire to achieve through these systems.