Microsoft did this by sacrificing other features of object storage that S3 and GS had since the beginning, primarily performance, automatic scaling, unlimited provisioning and cross-sectional (region wide) bandwidth. Azure blob storage did not have parity on those features back in 2015 and data platform applications could not be implemented on top of it as a result. Since then they fixed some of these, but there are still areas where Azure lacks scaling features that are taken for granted on AWS and GCP.