The check engine light tells you nothing. It tells your local mechanic nothing. Do you can't get the problem fixed easily or cheaply.
What it does, is force you to take the car to a dealer, who has the specialist, proprietary equipment needed to interpret the fault. And these gatekeepers will charge you a fat premium for that.
So no. I don't think this design choices are driven by a desire to serve the customer.
most people take it to a mechanic instead, because that's what they'd rather do.
There are plenty of proprietary codes that might set a malfunction light and not show up on an OBD reader, or not be interpreted by it.
(there are tools that reverse-engineer the proprietary protocols that can show those codes, but they aren't $20 - more like $200 and up)
I really don't see why you're defending hiding information. Even for someone who doesn't want to mess around and would just take it to a dealer, making the information available without the need for a code reader will not hurt in any way.
So yes - it’s the industry that got us screwed.