About 30 years or so ago, the "plug-it' type cords were a bit of a thing amongst European power tool manufacturers.
Whereas Festo/ol used hardwired power cabling, others like Elu, Atlas Copco, Kango, Kress, even B&D Professional grinders from their Italian factory all had plug-it type connectors, across a variety but not all of their tool range. These interchangable cables seem to have fallen rapidly from favour around the turn of the Millennium. About the time that Festo/ol & Protool started to adopt & adapt these connection cables across their ranges.
My own Festo & Festool items have been split about 50:50 with/without plug-its. I'm not really a huge fan of these potentially unreliable connectors either. I can see merit when sanding to be able to rapidly switch between different tools on the same job, but actually prefer to have 2 tools permanently attached to a double power adapter, with 2 independent extraction hoses individually fitted and leading back to a standard Festo Y-adapter. This is a much more reliable & rapid way of switching tools.
I suspect that other manufacturers have encountered reliability issues with their own proprietary modular power cable plug-it systems too, as the only companies still persisting with them these days are Festool & Mirka. Tellingly, the only other "manufacturer" that Mirka produce sander clones for that use their own plug-it type system is Metabo. Their other clients for whom they make sander clones - Rupes, Indasa, Delmeq, CarSystem & Sumake - all specify fixed power cabling.
Of course, cost of production may be another relevant factor: it's simply much cheaper to commission a job-lot of standard power pigtails from a subcontractor than to factor in the additional expense of producing proprietary plug-it cables (& sockets) from said supplier.
