I have not been to Japan, but generally my travel experience with internet access has been much more positive than yours. I've generally had good luck with getting on line in Europe, South America and even Southern Africa. Once in a while the internet might be down at a place I'm staying at, but usually it's quickly repaired. Exceptions to this are very rural areas, like in Patagonia and where I'm heading next week, Yellowstone National Park. There is really not internet available at most places in such remote areas.
We bought a data plan for one of our cell phones when my wife and I visited Sicily this spring. It was very handy to have this, even just to use google maps to find a destination and navigate us there. I don't do much calling when I travel so I really don't need the phone services. If I do, I have skype on my laptop and use that. I have only rarely had bandwidth problems with VOIP, but it can happen and it's frustrating when it does.
Hopefully this internet issue is not a developing trend. It's become a vital part of our lives and staying in touch with friends and family are important.