This shows how stupid Apple are (sic) at present then. It's a damn sight easier to add a code in to the existing software, knowing full well when they plan to release the device, which allows that device to download the beta. Than produce a separate beta for that device.
Wow. It would appear that some feel quite entitled...
Apple IS working on the issues, and it will be here when it gets here. This forum is full of threads about "half-baked" software, people complaining about bugs, flaws and issues... yet this thread is full of people clamoring for the release of iOS 11.3, quite possible before it's ready. One can only imagine the complexity of the code for iOS... and what may appear to be "a damn sight easier" to do something that you or I want, it may not actually be the case.
A little patience will, most likely, be rewarded.