They haven't "done it their own way". They've augmented the USB power interface in a backward compatible way so that you can still use standard USB cables, adapters and phones. That is absolutely not what Apple do, eg. their own Bluetooth, their own power/data connector, their own way of transferring music and files (iFT), their own programming language, etc, etc. None of which are compatible with the standard way that everyone else does the same things. Hence the "walled garden" accusation.
Yes they have. But as said already, it is not an issue.
If you want to use their propriety feature, you have to use their propriety cable, no?
Means having a cable lying around in the sitting room, another one in the sleeve with my anker charger, another one lying around in the caravan etc.
Not a massive problem, just a pain. Once the other 2 devices get updated, they'll be USB C too, and this will go away.
Its just an adoption issue, no biggie
Aye that's it really - just a case of building up the collection, or having a little adaptor handy to use when needed.