It seems to me that nowadays car batteries don't give as much warning as they used to when they're about to go bad. One day the car starts fine, and the next the car won't turn over. Unless you're testing them on a regular basis, I think it's hard to tell if they're on their way out.
You're right, the instrument panel can fool us into thinking the battery is still good. But I guess powering the car's computer and dashboard lights only requires a small amount of voltage and amperage compared to what's needed to turn the engine with the starter motor.
Whenever I have a starting issues, the battery is one of the first things I check. They are essentially "wear items" that require periodic replacement; and for the most part, it's one of the simple things an owner can still check and replace on their own. In my experience, replacement solves starting problems almost all the time. If I rule out the battery as a cause, then I start to worry a bit.