I worked at a startup that was using Azure. The reason was simple enough - it had been founded by finance people who were used to Excel, so Windows+Office was the non-negotiable first bit of IT they purchased. That created a sales channel Microsoft used to offer generous startup credits. The free money created a structural lack of discipline around spending. Once the startup credits ran out, the company became faced with a huge bill and difficulty motivating people to conserve funds.

At the start I didn't have any strong opinion on what cloud provider to use. I did want to do IT the "old fashioned way" - rent a big ass bare metal or cloud VM, issue UNIX user accounts on it and let people do dev/test/ad hoc servers on that. Very easy to control spending that way, very easy to quickly see what's using the resources and impose limits, link programs to people, etc. I was overruled as obviously old fashioned and not getting with the cloud programme. They ended up bleeding a million dollars a month and the company wasn't even running a SaaS!

I ended up with a very low opinion of Azure. Basic things like TCP connections between VMs would mysteriously hang. We got MS to investigate, they made a token effort and basically just admitted defeat. I raged that this was absurd as working TCP is table stakes for literally any datacenter since the 1980s, but - sad to say - at this time Azure's bad behavior was enabled by a widespread culture of CV farming in which "enterprise" devs were all obsessed with getting cloud tech onto their LinkedIn. Any time we hit bugs or stupidities in the way Azure worked I was told the problem was clearly with the software I'd written, which couldn't be "cloud native", as if it was it'd obviously work fine in Azure!

With attitudes like that completely endemic outside of the tech sector, of course Microsoft learned not to prioritize quality.

We did eventually diversify a bit. We needed to benchmark our server software reliably and that was impossible in Azure because it was so overloaded and full of noisy neighbours, so we rented bare metal servers in OVH to do that. It worked OK.