Today I deleted and recreated a SharePoint 2016 Web application and recreated it, without issue. Well, except that the new web application and site collection did not display the app launcher, otherwise known as the box of boxes in the upper left corner of the SharePoint 2016 window. As it turns out, the fix is fairly simple.
- Open SQL Server Management Studio
- Expand Security
- Double-click on the Portal App Pool account
- Click on Mapping
- Click on the Profile Database
- Check the box for SPDataAccess
- Click OK
- Refresh the SharePoint page in the browser
Enjoy!