"But instead of spending the money on a house big enough to host those dinner parties, you could host them at a fancy restaurant, with better food and the ability to spend the entire evening with the guests instead of in the kitchen."
That just not true. Restaurant quality has plummeted and it's easy to out cook them. Go to your average fancy wedding and the food is mediocre (this summer I went to a wedding in Canada's fanciest hotel. Same "fancy" fare you get anywhere else).
By the time your guests arrive, if you're spending your time in the kitchen instead of entertaining, you've messed up.
Also, you're telling OP how to live his life. You'd hate it if someone told you how to live yours.
"And for hosting occasional guests an extra bedroom, plenty of solutions exist for creating temporary sleeping space in the living room, while leaving your own bedroom to the guests. A small inconvenience to pay to save out a whole bedroom to pay for and maintain. There’s also the option of going on vacation together, which can be a really fun way to spend the holidays."
The carbon cost of vacations is not zero. Close the ducts to the extra room and maintaining it is essentially free.
But again, you're telling OP how to live. You do your vacations with friends, I'll invite my in-laws to stay with me for a year.
"Plenty of landscaping places will deliver to the home, much more convenient, and cheaper overall when you can downsize your vehicle of choice. I ended up making life choices that let me not have a car at all, and I spend that money on traveling instead."
And the detritus afterwards? Since I don't have a truck Ive been slowly cleaning my yard one green bin a week at a time since moving in two years ago. With a pickup I could have finished in two weekends.
Your travel is not environmentally sound at all. Sure, a plane gets 100 mpgp, if its full, but the distances are massive and its way worse overall.
But that's your life, you can choose to do that if you want. I care too much for the environment to air travel much (and, as a "third culture kid" -yuck- I actually do have friends and family scattered through out the world).
"My point is: I find life to be more comfortable when treating edge cases like edge cases, and finding an appropriate solution. I see so many people maxing out their house and car within their budget, and then talking about but never doing things they really want to, like that far away vacation, or that expensive hobby. I never quite understand why."
You don't have to understand. Ppl like to bitch. They would have even if their choices were different. That is a message of basically all religions throughout time - be content with your now.