We're likely to see changes made that will remain after fuel prices return to normal for sure, and there's some cool new technologies coming out.

I've noticed a lot more heavy electric trucks on the road, so we seem to be at a point where electric line haul is a reasonable goal, and almost every private vehicle sold new is either a hybrid or an EV. Commercial vehicle are a long way behind though, apart from the BYD shark, there's not a particularly impressive range available. The best option is the Ford Transit PHEV, but it's electric range isn't very impressive at all.

As we are already seeing, people will purchase less petrol and seek alternatives such as public transport;

This can only be a good thing. I would love to see public transport further subsidised (or free!) to help support this, though I know this disproportionately benefits those that live in large urban areas. I feel like we could fund this out of roads not built due to not needing them if public transport was better utilised.

Governments will adopt policies to support electrification of transport, logistics, agriculture, and industry (solar is already getting bipartisan support)

The previous government already did a lot in this space. I'd love to see a true investment in energy security in the form of large scale government investment in renewables (maybe use that $1B Luxon wants for gas storage) and perhaps a return of subsidies for electric vehicles.

Private businesses will make their own investments into electric infrastructure as it becomes more cost-effective for them to do so compared to running eg. diesel trucks or generators or boilers, or a fleet of petrol cars.

Trucks are an interesting case. Electric or hybrid trucks do exist, but the cost/benefit and hassle may not add up yet. I'd like to see the government provide better transport infrastructure. Instead of trucking everything up and down the country, can we get some incentives to use trains with trucks only for the last mile part of the trip?

The government is also already helping very large companies with moving to electric boilers, smelters, furnaces, etc. This is with a focus on CO2 emissions rather than reducing fuel usage, but they basically amount to the same thing. Most of the projects I know about were started under the previous government, I'm not sure if the current one has started any new ones.

single-use plastics made from petroleum products will become rare, and whichever materials scientists and chemical engineers can produce good replacements will have a product that will make millions.

I am not convinced plastics will be expensive enough in our lifetimes to make them anything but the cheapest option. And if like you say someone creates the perfect new material and makes millions, well then they will have a patent and everyone that doesn't want to pay through the teeth will stick to plastics.

The problem is that literally everything we make and consume in these modern industrial times, is dependent on petrochemical at some point, somewhere.

People talk about EVs being an alternative to petrol or diesel, but forget the petrochemicals used in mining lithium, making plastic, making electronics, lubricants, paint, etc etc for an EV. Just because it doesn't burn petrol doesn't mean practically every component it's made from requires oil at some stage, as do the components required to make solar panels or wind turbines. If the availability of fossil fuels turns into a shit-show, so will everything else.