High performance computing (HPC) is a specific field. Fast communication between compute nodes is very important and you won't get that on GCP or AWS where you may get 10gbs at the max. Most of the fast simulation codes are bounded by communication time between nodes.
Although, Azure is currently doing some HPC offerings.
Although, Azure is currently doing some HPC offerings.
https://azure.microsoft.com/en-us/solutions/big-compute/