Why so many laptop batteries?

Ever thought about the hundreds of different batteries that laptop computer manufacturers use? Have you ever stood back and wondered if there wasn't a better way?

I realize most people don't think about a new battery until the old one starts to deliver a little too little. But when that time comes, we begin to lament the fact that our laptop computer battery has to be very specific, and depending on the popularity of a particular laptop/battery combination, all too frequently the battery is scarce/expensive.

At one time Duracell tried to design a group of batteries that could  be standardized. This made sense because almost all laptop batteries then and now are made from the same 18650 cell. And the number of cells is almost always 6, 8, 9, or 12. They are just arranged differently... so there really aren't as many ways to make a laptop battery as there are out there.

So what went wrong? I'm not sure. Perhaps when the battery dies there are so many people that go and buy a new laptop that the manufacturers just can't ignore that kind of repeat business? Perhaps Duracell was charging too much for the privilege of using a standard cell? Perhaps there were features that laptop engineers wanted that a standard cell couldn't provide due to bloat or "jack of all trades means master of none." Maybe the tiny extra size requirement to use a standard battery was too much of a sacrifice compared to molding a new battery into the laptop design?

Let us know your ideas in the comments!