I think the issue is just that the popular Linux Desktop environments have now moved to GPU acceleration to match the Windows and MacOS counterparts, simply bec

I think the issue is just that the popular Linux Desktop environments have now moved to GPU acceleration to match the Windows and MacOS counterparts, simply because there's enough user demand for these features. However, lightweight desktop environments which don't rely on the GPU, like Xfce, MATE, and LXDE, absolutely still run on older hardware and can make it zip right along. The unsolvable problem for older hardware unfortunately is the web browser; there's nothing the operating system can do to make websites less complex, and more and more sites are becoming ridiculously bloated with scripts and media which will lag badly even on modern PCs. Still, ignoring the web browser element, Linux as an OS is highly flexible, and it can be made to run well on just about anything. That's still one of its core strengths.