Having done both, I can tell you that replacing the battery on an iPhone is already easier than an oil change on a typical car. The iPhone parts are expensive, but it's a relatively simple operation for a trained person.
Not to mention that an Apple battery replacement is about the same cost as having someone change the oil in your car if you use full synthetic. I just don't get the complaints. If the battery is dying, get a new one. If you don't want to spend the money, then Apple has provided a feature that lets your phone keep running.
Not to mention there are an infinite number of 5 minute tutorials on YouTube. You don't have to be trained, you just need a set of eyes and a brain. I'm glad an increasing number of phone manufacturers, not just Apple, put form factor and durability above user laziness.