I think it's more developers getting lazy. Why bother with SIMD and GPUs when you can write in a high level language like javascript, design with HTML / CSS, deploy your app with embedded libchromium and have a faster time to market. SSDs and fast CPUs have made efficient software somewhat of a rarity these days.
It not about being lazy, it's more about how can I get cross-platform GUI support that looks good without having to use C++? The answer seems to be html these days, unfortunately.