I still have a HTC One M8, which is almost 5 years old. The processor is fine, storage seems fine, battery is almost dead which is normal... But 2GB of RAM is now not enough for the same apps I've used for years. Open a few tabs in Firefox and it slows down a lot. Before quad core processors, I found the CPU was a serious bottleneck, as well.
And fwiw, Windows Mobile phones had full fledged browsers and 3G long before the iPhone.