I believe in climate change, but I don't believe that banning single use plastic bags from supermarkets and takeaways in NZ, and a few very well off people buying an EV instead of an ICE car are going to help. Maybe once we're able to ban plastic labels on fresh fruit we'll be getting somewhere.
Banning plastic bags and climate change aren't really related so you're right, banning plastics isn't going to help climate change 😉. The main reason for banning single-use plastic items is to prevent them ending up in the environment where they injure and kill wildlife, while also impacting human health once they get into our food sources.
You're also right that a few people buying EVs now isn't going to have a big impact right now. However, curbing our reliance on fossil fuels has to start somewhere and like with any new technology it was always going to start with those that have the financial capacity to be early adopters (these cars eventually become second hand cars where their prices are more in reach of a wider audience). As more of us who can afford to make the switch to an EV do, the cheaper the cars become and thus new EVs become available at lower budget levels.
Are you suggesting if we can't do it all at once then it's no point doing it at all?