It's sporting goods. It's reasonable for things to be compatible for a few years to keep things running. It's not reasonable for thirty years. Most people don't maintain interest that long or they want something new. The reasons for doing things one way are overwhelmed by new ways being better. It's reasonable for different companies to make different stuff to compete, there's no milspec to follow.
Freewheels and freehubs and drivers are a good example. Freewheel hubs had a proble, their limit on number of cogs and the poorly supported axles that started cracking when confronted with 7 speeds and mountain bikes. Freehubs fixed that and allowed for 12t top gear. The 8 speed version fixed a forward-compatibility problem with the 7 speed version that let it last until 11 speed, and allowed 11t top gear. But they incurred their own - especially that they put a lower limit on the cog size, and cogs digging in to the cog carrier. The xD driver solved those and allows a 9t top cog. I haven't looked a the new Shimano driver close enough to see if it's better than the xD or just deliberately different for business reasons. Will it stick? Shimano blew a lot of time getting on board but then they have a lot of market power. What's next? Not sure.
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Genesis 49:16-17