No company actually wants to make it easier for people to buy other tool brands.
With brandless batteries, it's luck-of-the-draw, but overall, as much as I do wish there were some way to know what you're getting, I've had good luck more often than not.
What's also been nice is the rise of adapters. My Bosch blue batteries now fit many places they didn't used to.
Some of these brandless Chinese makes are really solid, high quality products, but you can't easily tell which ones because they're visually indistinguishable from the bad ones.
Seems like the tool batteries might be the new ink cartridges.
Tool batteries as a general rule don't do anything fancy internally, so they are easily substituted. I suspect it's mostly a matter of the main buyers being tradies/workers who use them to make money and thus don't care that much about the expense of the batteries - they probably aren't replaced that often.
Would be nice if there was a 3rd-party seller known to use quality cells though, rather than unknown off brands.
And then not as any sort of special deal, just the standard retail bundle, the lawnmower with four batteries included costs $700. So that's $560 of batteries and $140 of lawnmower.
It's funny how lithium ion cell prices have absolutely cratered everywhere else, but the price of tool batteries just keeps going up.
I wish there was somebody making reputable quality compatible tool batteries instead of mystery brand counterfeit trash.