AWS were first and dominated.
Microsoft moved late with Azure, but as they had so many customers in B2B already with SQL Server and Office, that they soon grew market share. Google Cloud followed and acquired companies like Firebase to differentiate.
Market Share 2026
AWS 28%
Azure 21%
Google 14%
https://www.statista.com/chart/18819/worldwide-market-share-...
Anyone who’s actually used Azure knows it’s an unmitigated disaster for uptime. The problem is that this has been consistently true for like a decade now. This indicates real core architectural deficiencies they’ve been unable to address.