One of the reason that "street witnessing" and other alternatives to door to door work are being tried is because JWs are finding it more difficult to find people at home and more communities are restricted to any form of solicitation, religious or otherwise. This presents a problem of contacting people by the old method of door to door. So, it seems the Watchtower is reviving old methods and suggesting new ones. (One that has been tried in some areas is to approach people at shopping malls or other public areas.)
Some have wondered why the Watchtower has not extensively used TV and Radio ads to reach more people. It has been tried in a very limited way. But these ads cost money. And the Watchtower Society is very sensitive about spending any of their vast financial resources. It's easier and less expensive to have the rank and file use their resources instead.
However, the Watchtower Society may have to create new methods especially in the progressive countries. Most of the increases in recent years are in those "third world" catagory. And the people in those countries are in no position to donate their contributions to the Watchtower organization. They are more concerned with the necessities of life: food, shelter and clothing.