At first the task seems insuperable- rebuild the entire world in only 30 years to meet the challenges of global warming. Then you remember that most of this stuff will wear out and need to be replaced in 30 years anyway. Even the much-maligned "decay of our infrastructure" is in fact a wonderful asset- a long list of assets which are fully depreciated and paid for and can be abandoned with no financial penalty, or even some considerable gain.
Mid-20th century Americans did not build to last, because in their experience changing technology would render obsolete what they built. The enormous investments of railroads, in the early 1920s, in city stations and the coaling and other infrastructure that serviced the steam engines, were the last attempts to build infrastructure that would outlast the men and machines which built them. Less than 15 years later the automobile and diesel engine rendered all this investment by the railroads obsolete.
The problem, rendered in the "change on the fly " perspective, becomes two-fold. It's important to spend money on what we will need, and important not to spend money on what we won't need. We can see clearly that we will need stuff that runs on electricity, and we won't need stuff that runs on gas or oil.
If this were a dictatorship, things would be simple, and, quite probably, judging from other dictatorships, wrong. In our system, hundreds of thousands of decisions need to be made about where to spend. Fortunately, we have hundreds of thousands of governing bodies to consider these matters, breaking them into manageable sizes and then dealing with them, often by giving up something we want in order to get something we want more, and, often equally important, allowing funding for something we don't want in order to prevent something else we don't want even more.
This is where the tunnel-haters of Seattle get it so dreadfully wrong. Their policy is to take the approximately $1.5 billion the state would spend on the tunnel and spend it instead on suburban roads and highways, strengthening sprawl, while increasing the noise and pollution of the city by putting the traffic from 99 on the surface streets. Because they don't believe their own talking points, they don't believe that the tunnel will be a valuable rail ROW in the future. The same myopia informs their calls for bicycle paths- they simply can't envision a world in which significant amounts of the roadways are repurposed for other public uses.
That same amount of fury, expended in the cause of saving and extending Seattle's electric trolley buses, would be of real service to the future, spending money on infrastructure we'll need and taking money from "infrastructure repairs" we won't need that may actually harm us (South Park Bridge, I'm looking at you). The real lesson here, however, is probably that it won't pay to jump on a bandwagon that everybody says is going in the right direction.
Changing the world in 30 years won't be so hard if we do it one bus at a time. The devil is in the details.