Very true. . . I have recently been lamenting that "everybody's" batteries are incompatible with "everybody else's". . A pity ! . . Reason is obvious.
Battery-powered tools are incredibly convenient compared to the old way of first looking for a power outlet and then tripping over cords.
And battery-powered tools are here to stay, so I would think they could be a worthy target for legislated compatibility under "Go Green".
After all, automotive batteries are universal, so why not portable tool batteries ? . Could be in "everybody's" best interests to share that technology.