Google Docs or Google Drive as it is known today is a very useful tool but it has its limits. I use it for personal use all the time and I really don't know how I could operate with it. But for corporations it is little more complicated. In the end it depends on the size of the company. I worked for a tech start-up where we only had 6 employees (20 before I left) and Google Docs was such an easy way to share information. Also, since we didn't have a local server we can all access it was also a good way to share files that are too big to move via email.
For small companies it is a great tool at a very low price.
But as the company grows and the work they produce becomes more complicated and involves many more people C-Level individuals need to worry about potential security risks. This could be as simple as files being corrupted and a project's work is lost causing your team to do double work which could delay projects as well as give your company a bad reputation. There is also the possibility of another firm attempting to steal your work via hackers. Since Google Docs requires the company to open their network of files to Google or the Internet at large there is a gaping hole that IT needs to watch for potential risks. It becomes very easy for hackers to get behind the company firewall. Many projects have sensitive information about the company and our clients. There is no amount of potential savings that is worth ruining a comoany's reputation.
It can be used on a small scale for items deemed for public viewing in order to releive storage capicity on the local firewalled server. If this can be manged in a way that will not burden the IT department I would suggest using Google Docs but I cant imagine there is much savings in using Google and would onlu add another layer of confusion with employees as far as where files are.
I beleive that Google is working on creating a sense of security around thier system. Until they do so it will be very difficult for any C-Level employee to agree to use Google Docs or any other Cloud based system as a main source of storage. Companys who have secrets worth billions of dollars are not worried about saving 1, 2 or 10 million on storage facilities. In the end, if a company cant keep thier Intelectula property protected who would want to do business with them? So it isn't jsut the lsot money or the lose of conveniance, it is about the character and reputation of the company as whole. One bad move can seriously hurt potential growth and value of the company.