People go AWS because it’s the default, easy to hire people who know it, AWS are willing to throw credits at you if you’re in the US and once you’re on the platform it’s a serious effort to get off due to weird lock-ins.
Azure has its niche in the windows market, a lot of smaller orgs are going AzureAD as a replacement (or in addition to) a normal on-prem AD solution, once you’re on the platform it’s easy to just use more of it and consume existing contracts.
It helps immeasurably that if you’re running windows workloads they “happen” to be reasonably priced, as opposed to other cloud providers.
It’s a shame, because google cloud is definitely my favourite of the public clouds, I hope it doesn’t go anywhere and I’d be extremely happy to go back to it after using AWS for a while now.