I have been using Linux on the desktop since the late 90's. Other than increase hardware support, I have not tangentially noticed/felt almost anything you have mentioned here. When I fire up the desktop and load Firefox, I do not feel or see the sandboxing, the scheduler, the file system or the I/O. It just works.
Yes, we interact with it all the time but it isn't something that the end user would notice and that is a great thing. If you are not directly poking around with that stuff, you shouldn't notice it.
That they are so seamless should be seen as a badge of honor.
I also have been using Linux for over 20 years and I agree that hardware support is the most noticable.
This year I have installed Linux Mint on computers from people who wanted to jump from Windows to Linux. Every time I booted via USB, installed Linux and 10 minutes later everything was working.
This would not have happened 10 years ago. Back then there would always be an issue with a video driver, WiFi driver or audio driver.
Of course there are still hardware issues for some special deviced, but today Linux just runs fine for most people. And that's a great accomplishment.
Only on a select combination of blessed components and BIOS/EFI not half-ass broken to the tune it only worked somewhat stable on Windows.
Anything with split iGPU/dGPU was a mess no matter what and where, WiFi that was not Intel was a mess, suspend to ram and suspend to disk were a coin flip if the system would wake up again or if it would decide to wake up on its own and overheat itself to panic.
"I installed Ubuntu on peoples laptops and was extremely lucky they happened to have compatible hardware or didn't notice the stuff that didn't work and had a non-borked firmware". FTFY.
This was absolutely not everyones experience, including mine.
Yes, we interact with it all the time but it isn't something that the end user would notice and that is a great thing. If you are not directly poking around with that stuff, you shouldn't notice it.
That they are so seamless should be seen as a badge of honor.