You are right, the technology is available that provides us the tools for going paperless but it also represents a major change in the way we do business. In my experience, the lack of adoption company-wide, comes down to three things; cost, time and a willingness to change.
The benefits of being paperless are huge (supports mobile workforce, allows for faster decision making, improved security, etc. etc.) but it's not something most organizations can adopt overnight. Outfitting your workforce with the software and hardware required to capture, manage and retrieve information company wide (particularly if you have a mobile workforce) can be quite expensive. Even if the costs are easy to overcome, it's not as easy as downloading an app for mobile forms and being done with it. A true paperless office allows information to flow freely between different lines of business systems. For instance, a loan application filled out on a tablet in the client's living room has to be fed into different systems and to different users for action. Supporting documentation also needs to be included and verified. It can really be quite an involved process.
For a moment though let's say money is no object and you have a leadership team focused on going paperless, if you have an established workforce you still have to manage the change. I've seen companies go through all the planning, purchase the software, undergo intense implementation only to fail miserably on operator acceptance. It's best to involve all levels early in the process, make them feel they are part of the solution - not that it's simply being thrust on them.
All of that being said, where we have had great success in the past, is when we work with organizations who realize the best way to approach paperless in not "all or nothing". It's about understanding what they are doing now, where do they want to go, why there needs to be a change and where we can work together for the maximum impact. We develop a long-term road map to their ultimate destination but bite off one chunk (department, etc.) at a time.