Hi, you are observant!
Microsoft was actually represented at Inspire but they didn't sponsor this year. Sponsorships typically originate within their product groups and you will have seen Power BI ('16), Microsoft ML Server ('17) and SQL Data Warehouse ('18) sponsor Inspire. This year we are working on some other integrations but they are not so far along we've had a team step up, and each team approaches marketing differently.
That said, you may have seen their announcement at Build about the beta integration between Alteryx and Azure AutoML. And if you are interested, explore this https://gallery.alteryx.com/#!app/Microsoft-Azure-Machine-Learning-Tools/5cd9a3140462d7074ca54a11. Feedback is welcome!
Håkan Söderbom, Director, Technology Alliances