Yes and no - while it's still simple enough to replace parts in some cases, and said parts are usually easy enough to track down, manufacturers are starting to go the Apple route and lock the ECU to a given part, or require what boils down to a very expensive dongle to perform even simple maintenance procedures. Some of this is due to an actual need to recalibrate the vehicle due to minute differences in performance between parts, other cases are clearly laziness or malice.
For example, some modern Hyundai models require a very expensive ECU reprogramming tool to... release the electronic parking brake. So that you can change brake pads, a job that is normally well within the reach of anyone willing to get their hands dirty. I've seen suburban moms be shocked by how simple it is. And yet some vehicles now require a service at the dealership to change brake pads because they are the only ones who can command a parking brake unlock. What was wrong with the old pull handle or floor pedal parking brakes?
You can't tell me that all the features of an ECU reader couldn't be programmed into a modern head unit. The stereo is already on the CAN bus, why doesn't the stereo just pop up an alert that says e.g. "VSS Malfunction", "Oxygen Sensor Malfunction" instead of the cryptic check engine light requiring a special tool? Why don't our vehicles have a "maintenance mode" built into the head unit that can clear codes and recalibrate injector timings?
Even on early 2000s vehicles, there were usually procedures to do things like reprogramming key fobs by doing arcane things like cycling the key in the ignition 5 times while holding the brake pedal down. Old PCs had beep codes or blinkenlichten to tell you what the problem was when they couldn't POST, the only reason modern vehicles can't do the same is that automakers are looking for new revenue streams amid shrinking margins.
And this is aside from the fact that we have optimized for ease of construction rather than ease of repair, I saw a picture from a mechanic friend who works at a dealership recently, to replace a camshaft actuator on a modern Ford Bronco they had to lift the entire cab off the chassis. While I have seen home mechanics lift a cab a foot or two to access a part, it's well outside the ability of the average person to crane one of the heaviest parts of their vehicle several feet in the air.