The "silent computing" thing goes back to the first days of the Mac-and computers made in 1984 that cooked their analog boards to death because Steve Jobs was stubborn about them not having a fan. I managed to get my hands on one of the most original, untouched, un-upgraded "Macintoshes" I've ever seen from April 1984(they started shipping Feb. '84) and someone who knows these inside and out said despite it being basically untouched the analog board was 2 years newer than the rest. The problem was big enough that you had products like the Kensington "System Saver"-a fan(with a handy built in power strip) that "snaps" on to the top of the case and forces air through the convection vents.
The same thing repeated itself with the Cube, which ran so hot that it could never get past 500mhz and a Geforce 2MX(with a gigantic, non-standard heatsink) from the factory. The case has a fan bracket in it, and I've put a base fan in every Cube I've owned-of course it's essential if you fit a CPU or GPU upgrade(you really even need one if you put in a 2MX with a "standard" heatsink).
And, again, we've seen it in the trash can Mac Pro. Even though it has a fan(my Mac Pro 5,1 has 5 or so not counting the ones on the GPU, and G5s had 9), Apple admitted that they'd designed themselves into a "thermal corner" with the highest spec systems. Mac Pro 4,1s/5,1s can be built to exceed the performance of the 6,1(trash can) because of this-mine exceeds both the CPU single and multi-core performance of the 6,1, and if I wanted to give up running Snow Leopard I could get miles ahead of the GPU performance.
Unfortunately, having a laptop as thin as the current ones imposes its own thermal limits, and fans that move enough air are going to be loud.
This is probably a REALLY unpopular opinion and I'll probably get laughed out of here for it, but I'd love to see the pre-Retina Unibody case design come back. An i9 with NVMe PCIe storage and DDR4(socketed if you're feeling generous, Apple) would be incredible, especially if we could get an anti-glare retina screen. Even though that's a "big" computer by current Apple standards, it's still smaller/thinner than many PC laptops. The case is roomy enough that to move a lot more air than the current models and probably be no louder(if not quieter) while doing so.