Vertical would be if MS owned the carrier, the manufacturer, the operating system etc. Horizontal applies here where they own many interconnecting parts of the same layer of the market. Search, browser, email, etc, all being used to promote each other at the expense of competitors

I was actually a fan of Outlook for Android. Followed system dark mode before it was cool, had real multi account inbox, good wearos app, and other useful features. Then they started inserting Bing search into my long press menu system wide. And also recommending Edge when I clicked links. This kind of horizontal integration is just too baked into the company DNA. They can’t help themselves, even when it actually harms them