Yes? If your device costs £90 include everything it needs to run in the box.
If a manufacturer releases a device with a proprietary connector then I think it should be included as standard, but ideally they wouldn't and we'd all be using the same until a new standard is agreed, like USB C being the default.
Nintendo released the New 3DS without an adaptor and I had to go to a couple of stores and ended up buying a third-party version just to play the bloody thing for the first time, not cool.
But with micro USB I definitely don't want any more of these! It's a massive waste of resources when there are literally millions of these sitting in people's drawers, and that's not to mention the ecological impact.