A lot of times as new features are added out there and others are dropped. For instance, my wiped 2016 Razer Blade running Linux has no-longer-upgradable BIOS because of Razer's demand of Windows 10 to launch a GUI just to upgrade them. I'd like to migrate to another brand for the Spectre and Meltdown vulnerabilities alone, but the Nvidia 1060 is still good for most uses and it's hard to find a worthy replacement laptop with a hi-res screen supporting 100% AdobeRGB or DCI-P3 for photo work. Phones are hard to upgrade because now everyone wants to drop the 1/8-inch headphone jack I rely on.
I try to change my laptops due to increases in travel convenience. However, I find that my 10-year old Lenovo T410S keeps being most useful overall, even though I have bought several other laptops since I bought the Lenovo.
I bought an Asus X31 ultrabook because it was lighter and its SSD 'disk' was more resistant to shocks. But the miniscule size of the SSD meant that it was not much use as it could only store about a tenth of what the Lenovo could, with its upgraded 2TB HDD. Also the ultrabook's keyboard wasn't as good as the Lenovo's, apart from it not having a DVD reader, and it required adapters for ethernet, etc, instead of those connectors being built-in.
I also bought a Acer unit, but I 'killed' it. Can't remember the model, or what I did to kill it.