AWS has outages all the time as well, but due to the way AWS structures its offering, those outages only affect a relatively small portion of their customer base.
Even when Microsoft was being open about Azure having difficulty getting Intel chips, AWS, GCP etc. were in the same position and just not really talking about it. From my time in AWS there were some other times when some services with specialised hardware came really, really close to running out of capacity and had to scramble around with major internal "fire drills" against services to recoup capacity.
Most people won't run in to these issues, the clouds all tend to be good at it, but they still happen.
There are also advantages of the economy of scale and brand recognition. The more customers you have the more the capacity trends smooth out, the easier it is to predict need, even if you're still stuck with uncertainty on the ordering side.
If anything, I’m surprised we can just spin up a few hundred instances out of nowhere and not run into capacity issues.
MS also makes all sorts of crazy deals and commitments, and I wouldn’t be surprised if being collocated with a strategic customer may lead to local shortages of resources.
IDK what chips you are talking about, all x86 (which I assume is most of their compute) is Intel or AMD. If they make their own they are only making the ARM instances.
As far as chip shortages, it probably helps that Amazon makes its own chips. Microsoft could do the same rather than running out of capacity and blaming chip shortages.
Microsoft had to know that at some point they were going to run out of capacity. They should've either did something about it or let customers know.