Many of the planned deployments in US cities have been solutions in search of a problem. If a Wi-Fi network isn't available commercially you would have to question whether it's worth implementing at all.
In the last 20 years national governments have been progressively getting out of the business of running telecommunications networks. City governments who want to get into the network business should tread carefully or not at all.
Certainly, San Francisco muni Wi-Fi had "trophy network" written all over it. The project was dogged by political disputes from day one. Earthlink's suggestion that the city itself should pony up some cash was fair enough; the city's refusal was also sensible - it tells you it has other priorities, like housing the homeless.
Muni Wi-Fi in Philadelphia by contrast seems to have worked because it had the specific purpose of generating economic development in low-income parts of the city.
Here in Asia, the biggest muni Wi-Fi project, in Taipei, is falling short of its targets, having had signed just 30,000 users by April, barely 10% of the total expected.
Wi-Fi is a simple technology whose greatest strength is that it can be built bottoms-up - a sharp contrast to 3G. It doesn't need to be shoehorned into non-commercial projects.
For that reason, city mayors who want to ride the wireless wave and save taxpayers' money at the same time should foster community Wi-Fi networking like FON. FON operates shared Wi-Fi worldwide, has some smart investors like Skype and Google and has begun winning the confidence of some of the major ISPs.
It's done that without any government help at all - and that shouldn't come as a surprise.