I'd love to find out how many petrol cars there are on the road...

I'd love to find out how many petrol cars there are on the road in 30 years time. It is an immense timeline. Personally, I don't think many petrol cars will still be on the road, at least not in the richer countries.
I wouldn't be so sure about reselling value. Sure there is a resell market, there will always be one, question is do you get a value you'd consider fair right now. You're not allowed to enter Greater Paris with a diesel or old petrol car since 2021. Imagine what will be the case in 2 to 3 years time. In London you have to pay a daily charge if your car doesn't meet ultra low emission standards. So if you're from there, and you need a new (second hand) car, are you going for petrol? I'm not so sure. As the adoption of EVs further increases, it becomes much easier for governments to come up with other policies without a political backlash.

Sure, the classic argument of Australia being big, making everything difficult for the adoption of EVs is always there. To me though that is the glass half empty view. Australia has a population of about 25 million, Melbs+Sydney have a combined population of roughly 10 million. Sure, for some of the population an ICE right now is the only possibility (not necessarily true, as the range and facilities for EVs keeps improving), but the fast majority of the population will do fine with EVs. It is a matter of gov policy to push the transition fairly to the broader society and try not to leave the regional population or other groups disadvantaged in such a transition.

I agree with you on the electricity supply/price issue. That is a surprising problem here, given the wind and solar resources here. I think there needs to be a major grid upgrade to facilitate the transition. For that, the size of the country is indeed a problem. And a decentralized grid may solve some of those issues.

The sentiment in Germany reads to me as industry driven. Cars and car components is the primary export product of Germany. Unsurprisingly, the big car brands don't like to give up their combustion engines as they have been too slow in recognizing EVs market. Sounds like they are trying to slow down policies so they have more time to catch up. Hence, they don't mind hydrogen. All in my opinion of course.