Volvo is doing exactly that, it’s called Volvo Care if I’m not mistaken and includes some newer cars, service, maintenance, winter tires etc in a monthly fee.
Seems like Toyota Connected has similar projects in development - although maybe more focused for on-demand capabilities. Electric and self-driving capabilities aside - this sort of service subscription seems to have no major technological barriers; largely an operations + software problem. Seems like a good way to transition dealerships into service outlets towards larger scale fleet management.
In addition, Lincoln and Geely's Link and Co are also planning something like this.