Shimano Ultegra Di2 6800 rim brakes obsolescence?
OK, so I've decided to keep my gravel bike a gravel bike, take my Domane AL 2 to leave at our cabin. So now I'm looking at a used 2017 Domane SLR 7 with rim brakes for my daily riding at our home. It has the Ultegra Di2 6800 group (11 sp) with rim brakes. I actually like rim brakes but I'm concerned about obsolescence. I was told by the local Trek store that Shimano no longer makes electronic rim brake groupsets and that they couldn't replace parts in the future. However, the sales people here are notorious for trying to talk novices into thinking they need a $5k bike so I'm not sure what to believe. If I had to in the future, with rim brake di2 having become obsolete, could I change to mechanical shifting? Or would I be buying a bike with an expiration date on it? Because I don't think you can upgrade from rim brakes to disc since disc brakes have frames specifically designed for disc brake loads, correct?
Thanks!