If you ask me this was never meant to have any results you may be thinking of or at least, just marginal results. It is more a matter of efficiency.
- Makes it easy for older pioneers to get their hours in. Resulting on stronger year end reports. Keeps the R&F believing the preaching work is certainly accelerating (as the bible "predicts")
- Makes it easier for those with marginal hours (auxiliary pioneers) to actually become regular pioneers. Results same as above.
- But most importantly... if you read some of the statistics considered on this site and others, the number of preaching hours required to make a new convert are on the rise. The number of hours required to reach a house is still the same. Each JW still walks the same territories, same distances, etc. Therefore, if you want to reduce the number of hours that it takes to bring a new convert, you can only try to reduce the number of hours it takes to reach a person. Exposure in public places accomplishes that, thus increasing preaching efficiency. Besides, they used to go around looking for interested people, now the interested ones come to them.
In a nutshell, I do not know if it is working or not, but certainly, the purpose behind it seems clear to me.