Blame the lack of easy use of Access.
I routinely wanted to share out a simple sheet, allowable for anyone to edit easily, but have always fallen flat on my face by the complexity of simple tasks.
Yes I'm a novice user, however like Excel, I can use Calc or any similar thing because the interface is similar and or easy to use. I cannot use a database and have people interface with it to updated it without having to create a form, create a web interface or other complex things which are beyond my ability.
Now, you add database like abilities to Excel, and a lot more people would use them (like linking to other workbooks, multiple users editing simultaneously etc.)
Everyone gets help in Office suite, however Access remains the most neglected app. Only education or simplicity can change that, and people are not in the mood to learn new things*
*office drones, 9-5ers