Am I missing something? Most Bosch tools for instance use their universal battery packs, they fit nearly all old tools and it's a pretty safe bet that they will fit all the new ones too. There's plenty of 3rd party replacements on the market, but there's almost zero chance that you won't be able to buy a replacement battery for your bosch leaf blower in few years.

That's their standardised battery pack - it fits dozens of different tools: https://www.bosch-do-it.com/gb/en/diy/tools/battery-pack-pba...