The start menu search is just another instance of someone at MS trying to meet a KPI to drive search traffic to Bing. I believe there's a registry setting where you can turn the Bing search off and it'll go back to how search used to behave in the start menu.

And the ads/'recommended' apps are just another source of revenue from advertising. It's really strange to me. Windows isn't a free operating system, it still costs $140 retail for a Home license. But they sure treat their users like it is.