It may become simpler in some regards (drive train with fewer moving parts) but I think you can take your mind off the "do it yourself" part. The SW and electronics are always proprietary with little chance you'll ever (legally) have access to them. If anything their situation will get a lot worse as "always connected" cars become more common. Most likely trying to change/mod anything there will be detected and trigger some reaction that could go all the way to flagging your car as no longer street legal.

And what's left for you to repair? The simplicity you ask for will be introduced exactly where these home repairs used to happen: oil, filters, spark-plugs, a hose here, a cap there, etc. But the rest of the car stays mostly the same or gets even more complex. Most mechanical parts that aren't touched by the transition from ICE to electric motor could stay the same (suspensions, brakes), while the interior electronics will become more or less the equivalent of today's smartphones. Too complex for most people to try fixing themselves.