I switched to Linux because Windows kept getting s-l-o-w-e-r and slower over time no matter what I did. It was inevitable. Linux is still as fast as the day it was installed years later. I’m no techie and I do have problems with it from time to time but I get by.
I keep hearing about this phenomenon. Since I've been on Linux full-time (since 2000), I've either forgotten about it, or I switched before that started happening.
My Windows machines tend to not get a lot slower like most peoples' do. But it's probably like my phone doesn't get slower either. Why? Because I don't install a bunch of crap onto them. And what little I do install I tend to go into the startup sequence and remove them, thus those apps start in the background only when I want them to.
Exception apps are things like my DB that I have on my current Windows laptop. My boot process takes a while because I have MS SQL service start on bootup. But once it starts, my 4-year-old laptop flies (quad core, SSD, 32 GB RAM with 2400 MHz clock speed).
I’m running Linux Mint on what was, until last week, a Chromebook with 4GB of memory and 64GB of storage (ACER CB315-3H). I had to open it up and temporarily disconnect the battery to defeat the write protection as part of the install, but it was worth the time and trouble.