So here is my 2 cents.
I agree that AMD are in a very difficult spot and are burning through CASH at an alarming rate. This is driving them to cut costs and investments in R&D which is never a good story in a very competitive industry. They also got hammered by oversupply in the channels on the back of the whole bitcoin mining craze which they made a ton of cash off of in the short term but has impacted demand more than they expected due to used supply.
I suspect they have thrown a ton of cash at things like HBM as well - a typical ATI/AMD move like with tessellation, DX10/10.1, etc. jumping the gun - while GDDR5 is at the end of the road its not yet a significant performance bottleneck and shoving it onto the next round of cards will likely provide little real tangible benefit (that isn't to say there won't be performance increases at all) - I really don't understand them sometimes. We do need to get to it eventually but I'd be surprised if it couldn't have been done far more cost effectively.

