It does take a lot of time. That's why most people don't do it, and never will. That's specifically why society developed the way it did. Infrastructure developed to tackle the problems of getting food to folks that didn't grow crops, goods to people that couldn't make them. Human society has been aggressively de-localizing for the majority of its history.
By and large, I think this is a good thing. Oh, we can look at the negative environmental impacts of it. These are a problem, but I'm not sure they're a problem that can be solved in the long term by minimizing utilization of the infrastructure. It's a very short-term solution. There are extremely good reasons why our society doesn't make it easy to live locally: not all required (or desired goods) can be produced locally, regional pricing variations promote trade, craftsmen can increase income by targeting larger audiences, certain things are best produced on an economy of scale, etc. Then there's the issues of time- time spent canning preserves is time not used for other tasks. It a competitive economy, that is a potential liability.
Overall, the effects of de-localization are greater variety, a more just distribution of resources (this is not to say a just distribution- just more just), greater availability of resources, etc. It also drives technological development, general standard of living, live expectancy, etc.
The downsides are the resources consumed by the infrastructure- at a certain point we hit the scaling cap for any infrastructure. The resources consumed by the infrastructure will outweigh the benefits of using it. When we add in environmental costs, there's a definite concern about the sustainability of the current infrastructure.
Localized infrastructure is one proposed alternative, and it is a good one- so long as it doesn't get asked to scale well. Localized infrastructure can't support a city (although it can help). If everyone were to start shopping for locally produced items, the demand would outstrip supply very very quickly- driving prices up and sending people scrambling back into the current unhealthy infrastructure.
Both models, existing side by side, is a good, healthy arrangement. Obviously, no one but the mooniest of moon-bats is going to eschew all products that had to travel more than 50 miles. Who doesn't want some raspberries in January? But during the summer, it makes a great deal more sense to buy those raspberries from a local farm, or even grow them yourself.
We can't replace the current infrastructure with a more locally focused one. But we can use a locally focused one to balance the load and to provide limited fail-over capacity. And this gives us the opportunity to start working on replacing the current industrial infrastructure with something more robust, scalable and healthier.
I've rambled a long way from the original point. Living local and sustainable takes a great deal of individual time. There are positive social pressures that drive that time into other tasks. Localized economy is an excellent symbiont to large-scale industrial economies. They both benefit- but there's a diminishing return.
Mostly, I just find this absolutely interesting.