I have never done user research in an enterprise and not found Excel used for some reason by the audience. Many attempts have been made to build killer web apps and online spreadsheets that emulate or even replace Excel for some user group. The trouble is, the web is soooo far from offering a few key aspects that will be tough to top.
Excel offers control and reliability that the web lacks. If the web is down, so is the business for many people who rely on the data within a spreadsheet. That is a risk few are willing to take.
If someone decides or is asked to leave a company, Excel sheets can come with the user along with the ip therein. That level of security is tough to overcome with an online app.
The power to manipulate data and slice and dice it is where Excel… excels. The degree to which a user can manipulate data is far from being matched in any online app.
I am not at all saying excel is the ideal design. But if there is ever going to be an online experience that replaces Excel, there are a lot of challenges to overcome. Those challenges are not just functional. Another consideration – is that even a worthy pusuit?