I've been working from home for 5 years. Standing desk, Aeron chair, dual ultra wide monitors, it goes on and on.
It all adds up to about 1% of my compensation over those years.
I spend whatever it takes to have a great working environment, if I see something that will incrementally improve the 8 hours a day I spend working I immediately buy it. As far as my income goes it amounts to a rounding error.
>> there's a lot of people, including almost all the tech-oriented professionals under 30 that I know
That's called selection bias.
You have chosen to live in a location with expensive real estate. Good for you. Other people made different choices. I have rooms in my house I haven't been in for months.