Vendor lock-in on those batteries might not be quite as "lock-y" as other examples of vendor lock-in.

One can buy or print[1] cheap adaptors to use cross-brand batteries.

I wonder if it would be plausible to manufacture/sell a line of generic batteries with easily swappable adaptors for major brands, similar to how some AC/DC adaptors have a replaceable wall socket connection for different countries. Perhaps someone on HN knowledgeable on such things knows if there would be some technical or legal issue with that?

[1] https://www.printables.com/en/model/25735-18v-ryobi-one-to-m...