>No, you may want to run multiple threads, most people want to use their computer.
Whether most people know how their computer works or not, many want to be able to simultaneously: listen to music and/or watch a streaming video, browse multiple web pages, use text editors, specialized business applications, IDE's, and more.
You are going to have a bad time trying to do all of that on a single core, much less a single thread.
And having multiple cores just improves that ability. There's an upper limit to efficiency, but don't tell consumers that while you figure out your quantum processor :-)
Nowhere will you find me arguing that. In fact, this case was already captured in my comment. What you won't find is a single core desktop CPU that has the ability to run several threads concurrently well. The performance will necessarily decrease drastically as you add more concurrent threads.
There is a reason dual core has been standard for awhile. The performance of a single core on a multi-tasking machine is deplorable compared to a machine with additional cores.
Almost any modern desktop you buy (heck even phone) has around 4 cores, it's been this way for years now. After that point the average user doesn't see any particular gain in adding more cores. An 8 core machine really only helps power users. Most users are not running hundreds of threads, look at most your applications, they may have any number of threads running, but only one or two are ever loaded with data. This is the serial world we currently live in.
I'd guess 2 cores is still the majority of machines being sold, though 4 cores is probably a close second by now. 4 cores was certainly not standard on the majority of devices in the last few years.
Whether most people know how their computer works or not, many want to be able to simultaneously: listen to music and/or watch a streaming video, browse multiple web pages, use text editors, specialized business applications, IDE's, and more.
You are going to have a bad time trying to do all of that on a single core, much less a single thread.