Why do mobile websites still lag behind desktops in performance?

The laws of physics play a huge role here. For instance, a desktop CPU like the Ryzen 5500 can handle a lot more heat and power usage, which allows it to maintain high performance. Phones are built for efficiency and short bursts of power, so they can't match the sustained performance of a desktop.

Finally, ergonomics matter. While it may not seem relevant, the absence of hardware keyboards and mice on smartphones can impact user experience, leading to less optimization for mobile browsing compared to desktops.

Another factor is development practices. Many websites pull in large amounts of code, which can lead to slow load times. Developers often prioritize quicker builds over optimized code, which makes mobile sites less efficient.

There's definitely more at play. Mobile devices often run on cellular networks which can add latency. Plus, even though mobile CPUs have higher specs, they face strict power limits and thermal restrictions that desktop processors don't have. In terms of JavaScript, it's generally single-threaded, so the extra cores on mobile don’t help much.

One key reason is power conservation. Phones are designed to save battery life, while desktops can operate at full power without concern. This means that mobile devices can’t push their performance to the max without overheating, unlike desktops that can run continuously at high levels thanks to better cooling systems.