I don't disagree that the time frame is impractical, but the logic is sound. I'd say 10 to 15 years would be a more realistic time frame.
Remember that in 2007, the first iPhone was released & now, pretty much everyone is on some sort of multi-touch smartphone. It revolutionized the cell phone industry in only a few short years, and 10 years later, very few people have the old style flip phones or Nokias.
The key for the change will be infrastructure drying up. Gas stations don't make much money off of gas -- and instead on their convenience items with high mark-ups... especially cigarettes, sodas, snacks, and lottery tickets. If enough people switch to electric vehicles, gas stations will lose regular business & have to change their business models or close. Stations near interstates may switch to electric charging only. Many city gas stations might close because the electric cars wouldn't drive far enough to need a recharge while in town, and the city taxes for the lot wouldn't make the stations a good use of the land -- they might convert to fast food restaurants instead. (We already see this happening in big cities anyway -- mostly b/c of high rent and/or taxes or from offers to sell to more profitable industries). Once gas stations become scarce, people will worry about the range of their gas vehicles and finding stations to fuel up like we do now for electric vehicles. Mechanics will start to go out of business as fewer people need oil changes, tune-ups, and part replacements.
As an American, it seems far fetched, but in Europe, the electric car industry is well on its way to replacing fossil fuel burners. The UK is Tesla's biggest market & Norway isn't far behind. All major car manufacturers are developing electric vehicles & some nations have plans already to phase out oil burning cars entirely within only a few years.
Once the cost per unit gets low enough for the average new car consumer (like with the Tesla Model 3), and the total cost of ownership makes economic sense (many say it already is), then you reach a tipping point for conversion. 8 years is a long time in the tech industry, but not very long compared to the average life of a vehicle, so I'm inclined to think 10 to 15 years is a more reasonable number. The average person buys a new car every 2-5 years (I know... it's insane!) But, most will buy a new car within 10 to 15 years, so I think that's how long the switch will take as it'll be a very obvious choice.
As for big rigs, all manner of land based vehicles can easily be switched to electric. Electric vehicles are capable of much higher torque. They just need an adequate transmission in some cases where direct drive doesn't cut it. Planes will likely keep on using jet fuel for the foreseeable future, but land based travel will definitely go electric sooner or later. There's a great case for a domino effect that will throw oil based vehicles into a death spiral and push electric into the limelight within at least the next few decades if not sooner.