> There's no way you can do much on the rPi4 without active cooling.

You'd be surprised. YMMV and of course your local climate and your usage patterns do dictate how hot your gear runs, but in my experience adding a small 1$ heat spreader does allow my RPi4 to chug along without going over 60C. Heck, even placing it on the side or placing a coin stack over the processor is enough to keep it running along without ever throttling.

Of course if you're constantly running 100% CPU loads then you start to need cooling, whether it's your laptop or desktop or even servers.

There's an oversized passive heatsink available for the RPi4 now: https://www.coolipi.com/ Ought to be adequate at full load without a fan for anything short of a tropical climate. Not inexpensive, though.

You just need the right heatsink: http://move.rupy.se/file/pi_4.jpg

This one is sold out and out of production now though and I had to trim it because it was made for the 3+