Well.. I don't know what to say, I guess you should report those bugs to the appropriate vendors then. I don't believe a memory leak means we tell people to buy more memory :)
>"Primarily because any modern OS will throttle crazy runaway threads to ensure UI responsiveness" seems like you have a particular OS in mind, and I would be interested in hearing more.
Sure. You should read up about thread scheduling and how an OS scheduler works. I don't think I can explain that in a comment, and I'd do a poor job anyway.
>I do not observe that behaviour on Debian 9 (and other Linux distros), Mac OS X, and Windows 7/8. I regularly bring any of those to UI stuttering/freeze from various workloads. Webapps only really breaks the lesser ones singlehandedly though (most of my other systems are 4+ core with 32GB+ RAM).
I don't observe that behavior. Just for fun I ran a CPU Stress test (https://silver.urih.com/) as I'm typing this comment. CPU pegged at 100%. Not feeling a thing... https://imgur.com/a/J0l9VaP