It is unclear why Microsoft has retired the service.
Maybe the executive who was pushing for it got bored.
Microsoft's Azure Video Analyzer service is being put out to pasture, with its termination notice arriving less than a year after the preview was unveiled at the company's 2021 Build event. The shutters will be pulled down for good on November 30 and Microsoft has warned that from December 2 2022, "your Azure Video Analyzer …
why renting tech instead of buying it is bad. M$ got a few people to use it, they probably now depend upon it, but because not enough people use it M$ decided to cut it and now those who now rely on it are screwed. Had this been purchased, those that rely on it could have kept using it.