Don't delude yourself into thinking the cons are not important. If your users don't accept the electronic documentation, they just may find a different product to use or call your technical support more than you would like. These situations can hurt your business more than continuing to incur the cost of paper. Many people like to take a manual with them, turn down or mark up the important pages, and create tabs to find what they want quickly. I know you can do some of those things with today's electronic documents, but somehow it's not the same.
Some people just feel more comfortable with paper.
These issues are not likely to go away soon, though they will probably diminish with time. Young people who have grown up with computers and video games may accept online documentation more readily than those of us who did not. Now, don't get the wrong idea. I am not against online documentation. I believe it can be very valuable, and I both use and create it.