I think the blame can be put on the closed ecosystems of phones. On laptops and desktops, with the possibility to install any OS, it's more often possible to meet the requirements of up-to-date frameworks using the same hardware. My laptop is from 2010 and is still running everything I want, it's up to date and responsive. With the current hardware of phones, and even their hardware of 6 years ago, I don't see any reason why they should be changed, other than being closed platforms where one cannot control the OS.