Not naive at all! That is a genuinely good question with a rather dissatisfying answer: it depends. 'Most' is the tricky word there. It feels a bit like recycling, where you make it a habit but it isn't always easy to see the benefits of the effort, if that makes sense. The work is bound by the client and the code, and the client is usually mostly concerned with the budget. I always make an effort to push better materials and practices, while also going above and beyond on building envelope and HVAC systems to make the houses I design as efficient as possible, then pricing comes in and a lot of that is the first to go. I'm probably doing the most I can at my current job. I could probably do more at a more climate positive firm (not always easy depending on location). I might be able to do a lot more abandoning the mainstream practice of architecture altogether and finding a job that utilizes at least some of my existing skillset, but what that means isn't always clear. Hope that answered your question! Apologies for rambling

My thoughts too. Every month a new house is built in my neighborhood, and almost every time they chop down a shade-giving, 150-year-old tree.

Maybe you could commit (and convince your peers) to design buildings around the trees, and in other environmentally-friendly ways (supporting clean runoff water, re-wilding as much as possible, green roofs etc)?

You could probably figure out ways to build houses to make it harder to chop down trees in the future. That would be cool.