Looking at this graphic, this is no way lists all of the versions of Excel which Microsoft sells. What about Office 365 Enterprise E1? Surely you would get Power Pivot functionality with that right? No. How much more money is Power Pivot going to cost you? Well, if you have Office 365, you are paying $8 a month for the Office software, including Excel. There is no guarantee that spending more money will provide Power Pivot though. Office 365 ProPlus, which has Power Pivot, will run you $12 a month. If you have Office Small Business Premium, which runs $12.50 a month you won’t get Power Pivot. Check the version of Excel 2016 by going to File->Account then look at what is listed. If the version isn’t Office 365 Pro Plus or one of the other versions listed in the graphic, there will be no way to make Power Pivot appear.
Based on Ginger’s explanation this seems like something that will be very confusing for some Excel users.